diff --git a/GraphicsView/demo/Alpha_shapes_2/CMakeLists.txt b/GraphicsView/demo/Alpha_shapes_2/CMakeLists.txt
index ca4a58c5958..771664f2a4b 100644
--- a/GraphicsView/demo/Alpha_shapes_2/CMakeLists.txt
+++ b/GraphicsView/demo/Alpha_shapes_2/CMakeLists.txt
@@ -13,31 +13,31 @@ if(POLICY CMP0071)
   cmake_policy(SET CMP0071 NEW)
 endif()
 
-find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt5)
+find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt6)
 
-find_package(Qt5 QUIET COMPONENTS Script OpenGL Svg)
+find_package(Qt6 QUIET COMPONENTS OpenGLWidgets Svg)
 include_directories(BEFORE ./include)
 
-if(CGAL_Qt5_FOUND AND Qt5_FOUND)
+if(CGAL_Qt6_FOUND AND Qt6_FOUND)
   add_definitions(-DQT_NO_KEYWORDS)
   set(CMAKE_INCLUDE_CURRENT_DIR ON)
   set(CMAKE_AUTOMOC ON)
 
   # UI files (Qt Designer files)
-  qt5_wrap_ui(DT_UI_FILES Alpha_shapes_2.ui)
+  qt6_wrap_ui(DT_UI_FILES Alpha_shapes_2.ui)
 
   # qrc files (resources files, that contain icons, at least)
-  qt5_add_resources(CGAL_Qt5_RESOURCE_FILES ./Alpha_shapes_2.qrc)
+  qt6_add_resources(CGAL_Qt6_RESOURCE_FILES ./Alpha_shapes_2.qrc)
 
   # The executable itself.
   add_executable(
-    Alpha_shapes_2 Alpha_shapes_2.cpp ${DT_UI_FILES} ${CGAL_Qt5_RESOURCE_FILES}
-                   ${CGAL_Qt5_MOC_FILES})
+    Alpha_shapes_2 Alpha_shapes_2.cpp ${DT_UI_FILES} ${CGAL_Qt6_RESOURCE_FILES}
+                   ${CGAL_Qt6_MOC_FILES})
 
   add_to_cached_list(CGAL_EXECUTABLE_TARGETS Alpha_shapes_2)
 
-  target_link_libraries(Alpha_shapes_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt5
-                                               Qt5::Gui)
+  target_link_libraries(Alpha_shapes_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt6
+                                               Qt6::Gui)
 
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(Alpha_shapes_2)
@@ -45,5 +45,5 @@ if(CGAL_Qt5_FOUND AND Qt5_FOUND)
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(Alpha_shapes_2)
 else()
-  message("NOTICE: This demo requires CGAL and Qt5, and will not be compiled.")
+  message("NOTICE: This demo requires CGAL and Qt6, and will not be compiled.")
 endif()
diff --git a/GraphicsView/demo/Apollonius_graph_2/CMakeLists.txt b/GraphicsView/demo/Apollonius_graph_2/CMakeLists.txt
index ab0f43011f9..27a13e4b21c 100644
--- a/GraphicsView/demo/Apollonius_graph_2/CMakeLists.txt
+++ b/GraphicsView/demo/Apollonius_graph_2/CMakeLists.txt
@@ -13,32 +13,32 @@ if(POLICY CMP0071)
   cmake_policy(SET CMP0071 NEW)
 endif()
 
-find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt5)
+find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt6)
 
-find_package(Qt5 QUIET COMPONENTS Script OpenGL Svg)
+find_package(Qt6 QUIET COMPONENTS OpenGLWidgets Svg)
 
-if(CGAL_Qt5_FOUND AND Qt5_FOUND)
+if(CGAL_Qt6_FOUND AND Qt6_FOUND)
   add_definitions(-DQT_NO_KEYWORDS)
   set(CMAKE_INCLUDE_CURRENT_DIR ON)
   set(CMAKE_AUTOMOC ON)
   #--------------------------------
   # UI files (Qt Designer files)
-  qt5_wrap_ui(DT_UI_FILES Apollonius_graph_2.ui)
+  qt6_wrap_ui(DT_UI_FILES Apollonius_graph_2.ui)
 
   # qrc files (resources files, that contain icons, at least)
-  qt5_add_resources(CGAL_Qt5_RESOURCE_FILES ./Apollonius_graph_2.qrc)
+  qt6_add_resources(CGAL_Qt6_RESOURCE_FILES ./Apollonius_graph_2.qrc)
 
   # use the Qt MOC preprocessor on classes that derives from QObject
 
   # The executable itself.
   add_executable(
     Apollonius_graph_2 Apollonius_graph_2.cpp ${DT_UI_FILES}
-                       ${CGAL_Qt5_RESOURCE_FILES} ${CGAL_Qt5_MOC_FILES})
+                       ${CGAL_Qt6_RESOURCE_FILES} ${CGAL_Qt6_MOC_FILES})
 
   add_to_cached_list(CGAL_EXECUTABLE_TARGETS Apollonius_graph_2)
 
-  target_link_libraries(Apollonius_graph_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt5
-                                                   Qt5::Gui)
+  target_link_libraries(Apollonius_graph_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt6
+                                                   Qt6::Gui)
 
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(Apollonius_graph_2)
@@ -46,5 +46,5 @@ if(CGAL_Qt5_FOUND AND Qt5_FOUND)
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(Apollonius_graph_2)
 else()
-  message("NOTICE: This demo requires CGAL and Qt5, and will not be compiled.")
+  message("NOTICE: This demo requires CGAL and Qt6, and will not be compiled.")
 endif()
diff --git a/GraphicsView/demo/Bounding_volumes/CMakeLists.txt b/GraphicsView/demo/Bounding_volumes/CMakeLists.txt
index 69a30838cea..3325c437903 100644
--- a/GraphicsView/demo/Bounding_volumes/CMakeLists.txt
+++ b/GraphicsView/demo/Bounding_volumes/CMakeLists.txt
@@ -13,34 +13,34 @@ if(POLICY CMP0071)
   cmake_policy(SET CMP0071 NEW)
 endif()
 
-find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt5)
+find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt6)
 
-find_package(Qt5 QUIET COMPONENTS Script OpenGL Svg)
+find_package(Qt6 QUIET COMPONENTS OpenGLWidgets Svg)
 include_directories(BEFORE ./include)
 
-if(CGAL_Qt5_FOUND AND Qt5_FOUND)
+if(CGAL_Qt6_FOUND AND Qt6_FOUND)
 
   set(CMAKE_INCLUDE_CURRENT_DIR ON)
   add_definitions(-DQT_NO_KEYWORDS)
   set(CMAKE_AUTOMOC ON)
 
   # UI files (Qt Designer files)
-  qt5_wrap_ui(DT_UI_FILES Bounding_volumes.ui)
+  qt6_wrap_ui(DT_UI_FILES Bounding_volumes.ui)
 
   # qrc files (resources files, that contain icons, at least)
-  qt5_add_resources(CGAL_Qt5_RESOURCE_FILES ./Bounding_volumes.qrc)
+  qt6_add_resources(CGAL_Qt6_RESOURCE_FILES ./Bounding_volumes.qrc)
 
   # use the Qt MOC preprocessor on classes that derives from QObject
 
   # The executable itself.
   add_executable(
     Bounding_volumes Bounding_volumes.cpp ${DT_UI_FILES}
-                     ${CGAL_Qt5_RESOURCE_FILES} ${CGAL_Qt5_MOC_FILES})
+                     ${CGAL_Qt6_RESOURCE_FILES} ${CGAL_Qt6_MOC_FILES})
 
   add_to_cached_list(CGAL_EXECUTABLE_TARGETS Bounding_volumes)
 
-  target_link_libraries(Bounding_volumes PRIVATE CGAL::CGAL CGAL::CGAL_Qt5
-                                                 Qt5::Gui)
+  target_link_libraries(Bounding_volumes PRIVATE CGAL::CGAL CGAL::CGAL_Qt6
+                                                 Qt6::Gui)
 
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(Bounding_volumes)
@@ -50,6 +50,6 @@ if(CGAL_Qt5_FOUND AND Qt5_FOUND)
 
 else()
 
-  message("NOTICE: This demo requires CGAL and Qt5, and will not be compiled.")
+  message("NOTICE: This demo requires CGAL and Qt6, and will not be compiled.")
 
 endif()
diff --git a/GraphicsView/demo/Circular_kernel_2/CMakeLists.txt b/GraphicsView/demo/Circular_kernel_2/CMakeLists.txt
index eb2e2b79011..129bcd076b8 100644
--- a/GraphicsView/demo/Circular_kernel_2/CMakeLists.txt
+++ b/GraphicsView/demo/Circular_kernel_2/CMakeLists.txt
@@ -13,32 +13,32 @@ if(POLICY CMP0071)
   cmake_policy(SET CMP0071 NEW)
 endif()
 
-find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt5)
+find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt6)
 
-find_package(Qt5 QUIET COMPONENTS Script OpenGL Svg)
+find_package(Qt6 QUIET COMPONENTS OpenGLWidgets Svg)
 
-if(CGAL_Qt5_FOUND AND Qt5_FOUND)
+if(CGAL_Qt6_FOUND AND Qt6_FOUND)
   add_definitions(-DQT_NO_KEYWORDS)
   set(CMAKE_INCLUDE_CURRENT_DIR ON)
   set(CMAKE_AUTOMOC ON)
 
   # UI files (Qt Designer files)
-  qt5_wrap_ui(DT_UI_FILES Circular_kernel_2.ui)
+  qt6_wrap_ui(DT_UI_FILES Circular_kernel_2.ui)
 
   # qrc files (resources files, that contain icons, at least)
-  qt5_add_resources(CGAL_Qt5_RESOURCE_FILES ./Circular_kernel_2.qrc)
+  qt6_add_resources(CGAL_Qt6_RESOURCE_FILES ./Circular_kernel_2.qrc)
 
   # use the Qt MOC preprocessor on classes that derives from QObject
 
   # The executable itself.
   add_executable(
     Circular_kernel_2 Circular_kernel_2.cpp ${DT_UI_FILES}
-                      ${CGAL_Qt5_RESOURCE_FILES} ${CGAL_Qt5_MOC_FILES})
+                      ${CGAL_Qt6_RESOURCE_FILES} ${CGAL_Qt6_MOC_FILES})
 
   add_to_cached_list(CGAL_EXECUTABLE_TARGETS Circular_kernel_2)
 
-  target_link_libraries(Circular_kernel_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt5
-                                                  Qt5::Gui)
+  target_link_libraries(Circular_kernel_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt6
+                                                  Qt6::Gui)
 
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(Circular_kernel_2)
@@ -48,6 +48,6 @@ if(CGAL_Qt5_FOUND AND Qt5_FOUND)
 
 else()
 
-  message("NOTICE: This demo requires CGAL and Qt5, and will not be compiled.")
+  message("NOTICE: This demo requires CGAL and Qt6, and will not be compiled.")
 
 endif()
diff --git a/GraphicsView/demo/Generator/CMakeLists.txt b/GraphicsView/demo/Generator/CMakeLists.txt
index 3be28ec735d..58346ad7753 100644
--- a/GraphicsView/demo/Generator/CMakeLists.txt
+++ b/GraphicsView/demo/Generator/CMakeLists.txt
@@ -12,36 +12,36 @@ if(POLICY CMP0071)
   cmake_policy(SET CMP0071 NEW)
 endif()
 
-find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt5)
+find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt6)
 
-find_package(Qt5 QUIET COMPONENTS Script OpenGL Svg)
+find_package(Qt6 QUIET COMPONENTS OpenGLWidgets Svg)
 
-if(CGAL_Qt5_FOUND AND Qt5_FOUND)
+if(CGAL_Qt6_FOUND AND Qt6_FOUND)
 
   add_definitions(-DQT_NO_KEYWORDS)
   set(CMAKE_INCLUDE_CURRENT_DIR ON)
   set(CMAKE_AUTOMOC ON)
 
   # UI files (Qt Designer files)
-  qt5_wrap_ui(DT_UI_FILES Generator_2.ui)
+  qt6_wrap_ui(DT_UI_FILES Generator_2.ui)
 
   # qrc files (resources files, that contain icons, at least)
-  qt5_add_resources(CGAL_Qt5_RESOURCE_FILES ./Generator_2.qrc)
+  qt6_add_resources(CGAL_Qt6_RESOURCE_FILES ./Generator_2.qrc)
 
   # use the Qt MOC preprocessor on classes that derives from QObject
 
   # The executable itself.
   add_executable(Generator_2 Generator_2.cpp ${DT_UI_FILES}
-                             ${CGAL_Qt5_RESOURCE_FILES} ${CGAL_Qt5_MOC_FILES})
+                             ${CGAL_Qt6_RESOURCE_FILES} ${CGAL_Qt6_MOC_FILES})
 
   add_to_cached_list(CGAL_EXECUTABLE_TARGETS Generator_2)
 
-  target_link_libraries(Generator_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt5 Qt5::Gui)
+  target_link_libraries(Generator_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt6 Qt6::Gui)
 
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(Generator_2)
 else()
 
-  message("NOTICE: This demo requires CGAL and Qt5, and will not be compiled.")
+  message("NOTICE: This demo requires CGAL and Qt6, and will not be compiled.")
 
 endif()
diff --git a/GraphicsView/demo/GraphicsView/CMakeLists.txt b/GraphicsView/demo/GraphicsView/CMakeLists.txt
index 51617b00b87..4b3940bf0fa 100644
--- a/GraphicsView/demo/GraphicsView/CMakeLists.txt
+++ b/GraphicsView/demo/GraphicsView/CMakeLists.txt
@@ -12,25 +12,25 @@ if(POLICY CMP0071)
   cmake_policy(SET CMP0071 NEW)
 endif()
 
-find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt5)
+find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt6)
 
-find_package(Qt5 QUIET COMPONENTS Script OpenGL Svg)
+find_package(Qt6 QUIET COMPONENTS Widgets OpenGLWidgets Svg)
 
-if(CGAL_Qt5_FOUND AND Qt5_FOUND)
+if(CGAL_Qt6_FOUND AND Qt6_FOUND)
 
   add_definitions(-DQT_NO_KEYWORDS)
   set(CMAKE_INCLUDE_CURRENT_DIR ON)
 
-  add_executable(min min.cpp ${CGAL_Qt5_RESOURCE_FILES} ${CGAL_Qt5_MOC_FILES})
+  add_executable(min min.cpp ${CGAL_Qt6_RESOURCE_FILES} ${CGAL_Qt6_MOC_FILES})
 
   add_to_cached_list(CGAL_EXECUTABLE_TARGETS min)
 
-  target_link_libraries(min PRIVATE CGAL::CGAL CGAL::CGAL_Qt5 Qt5::Gui)
+  target_link_libraries(min PRIVATE CGAL::CGAL CGAL::CGAL_Qt6 Qt6::Gui)
 
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(min)
 else()
 
-  message("NOTICE: This demo requires CGAL and Qt5, and will not be compiled.")
+  message("NOTICE: This demo requires CGAL and Qt6, and will not be compiled.")
 
 endif()
diff --git a/GraphicsView/demo/L1_Voronoi_diagram_2/CMakeLists.txt b/GraphicsView/demo/L1_Voronoi_diagram_2/CMakeLists.txt
index 432cb655369..b5e8e231bde 100644
--- a/GraphicsView/demo/L1_Voronoi_diagram_2/CMakeLists.txt
+++ b/GraphicsView/demo/L1_Voronoi_diagram_2/CMakeLists.txt
@@ -13,32 +13,32 @@ if(POLICY CMP0071)
   cmake_policy(SET CMP0071 NEW)
 endif()
 
-find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt5)
+find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt6)
 
-find_package(Qt5 QUIET COMPONENTS Script OpenGL Svg)
+find_package(Qt6 QUIET COMPONENTS OpenGLWidgets Svg)
 include_directories(BEFORE ./include)
 
-if(CGAL_Qt5_FOUND AND Qt5_FOUND)
+if(CGAL_Qt6_FOUND AND Qt6_FOUND)
 
   add_definitions(-DQT_NO_KEYWORDS)
   set(CMAKE_INCLUDE_CURRENT_DIR ON)
   set(CMAKE_AUTOMOC ON)
 
   # UI files (Qt Designer files)
-  qt5_wrap_ui(DT_UI_FILES L1_voronoi_diagram_2.ui)
+  qt6_wrap_ui(DT_UI_FILES L1_voronoi_diagram_2.ui)
 
   # qrc files (resources files, that contain icons, at least)
-  qt5_add_resources(CGAL_Qt5_RESOURCE_FILES ./L1_voronoi_diagram_2.qrc)
+  qt6_add_resources(CGAL_Qt6_RESOURCE_FILES ./L1_voronoi_diagram_2.qrc)
 
   # The executable itself.
   add_executable(
     L1_voronoi_diagram_2 L1_voronoi_diagram_2.cpp ${DT_UI_FILES}
-                         ${CGAL_Qt5_RESOURCE_FILES} ${CGAL_Qt5_MOC_FILES})
+                         ${CGAL_Qt6_RESOURCE_FILES} ${CGAL_Qt6_MOC_FILES})
 
   add_to_cached_list(CGAL_EXECUTABLE_TARGETS L1_voronoi_diagram_2)
 
-  target_link_libraries(L1_voronoi_diagram_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt5
-                                                     Qt5::Gui)
+  target_link_libraries(L1_voronoi_diagram_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt6
+                                                     Qt6::Gui)
 
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(L1_voronoi_diagram_2)
@@ -48,6 +48,6 @@ if(CGAL_Qt5_FOUND AND Qt5_FOUND)
 
 else()
 
-  message("NOTICE: This demo requires CGAL and Qt5, and will not be compiled.")
+  message("NOTICE: This demo requires CGAL and Qt6, and will not be compiled.")
 
 endif()
diff --git a/GraphicsView/demo/Largest_empty_rect_2/CMakeLists.txt b/GraphicsView/demo/Largest_empty_rect_2/CMakeLists.txt
index a6de2468c40..7c83ab38c01 100644
--- a/GraphicsView/demo/Largest_empty_rect_2/CMakeLists.txt
+++ b/GraphicsView/demo/Largest_empty_rect_2/CMakeLists.txt
@@ -13,36 +13,36 @@ if(POLICY CMP0071)
   cmake_policy(SET CMP0071 NEW)
 endif()
 
-find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt5)
+find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt6)
 
-find_package(Qt5 QUIET COMPONENTS Script OpenGL Svg)
+find_package(Qt6 QUIET COMPONENTS OpenGLWidgets Svg)
 
-if(CGAL_Qt5_FOUND AND Qt5_FOUND)
+if(CGAL_Qt6_FOUND AND Qt6_FOUND)
 
   add_definitions(-DQT_NO_KEYWORDS)
   set(CMAKE_INCLUDE_CURRENT_DIR ON)
   set(CMAKE_AUTOMOC ON)
 
   # UI files (Qt Designer files)
-  qt5_wrap_ui(DT_UI_FILES Largest_empty_rectangle_2.ui)
+  qt6_wrap_ui(DT_UI_FILES Largest_empty_rectangle_2.ui)
 
   # qrc files (resources files, that contain icons, at least)
-  qt5_add_resources(CGAL_Qt5_RESOURCE_FILES ./Largest_empty_rectangle_2.qrc)
+  qt6_add_resources(CGAL_Qt6_RESOURCE_FILES ./Largest_empty_rectangle_2.qrc)
 
   # The executable itself.
   add_executable(
     Largest_empty_rectangle_2 Largest_empty_rectangle_2.cpp ${DT_UI_FILES}
-                              ${CGAL_Qt5_RESOURCE_FILES} ${CGAL_Qt5_MOC_FILES})
+                              ${CGAL_Qt6_RESOURCE_FILES} ${CGAL_Qt6_MOC_FILES})
 
   add_to_cached_list(CGAL_EXECUTABLE_TARGETS Largest_empty_rectangle_2)
 
   target_link_libraries(Largest_empty_rectangle_2
-                        PRIVATE CGAL::CGAL CGAL::CGAL_Qt5 Qt5::Gui)
+                        PRIVATE CGAL::CGAL CGAL::CGAL_Qt6 Qt6::Gui)
 
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(Largest_empty_rectangle_2)
 else()
 
-  message("NOTICE: This demo requires CGAL and Qt5, and will not be compiled.")
+  message("NOTICE: This demo requires CGAL and Qt6, and will not be compiled.")
 
 endif()
diff --git a/GraphicsView/demo/Periodic_2_triangulation_2/CMakeLists.txt b/GraphicsView/demo/Periodic_2_triangulation_2/CMakeLists.txt
index 2f964941bb0..0cae7c97901 100644
--- a/GraphicsView/demo/Periodic_2_triangulation_2/CMakeLists.txt
+++ b/GraphicsView/demo/Periodic_2_triangulation_2/CMakeLists.txt
@@ -10,22 +10,22 @@ if(POLICY CMP0071)
   cmake_policy(SET CMP0071 NEW)
 endif()
 
-find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt5)
+find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt6)
 
-find_package(Qt5 QUIET COMPONENTS Script OpenGL Svg)
+find_package(Qt6 QUIET COMPONENTS OpenGLWidgets Svg)
 include_directories(BEFORE ./include)
 
-if(CGAL_Qt5_FOUND AND Qt5_FOUND)
+if(CGAL_Qt6_FOUND AND Qt6_FOUND)
 
   add_definitions(-DQT_NO_KEYWORDS)
   set(CMAKE_INCLUDE_CURRENT_DIR ON)
   set(CMAKE_AUTOMOC ON)
 
   # UI files (Qt Designer files)
-  qt5_wrap_ui(DT_UI_FILES Periodic_2_triangulation_2.ui)
+  qt6_wrap_ui(DT_UI_FILES Periodic_2_triangulation_2.ui)
 
   # qrc files (resources files, that contain icons, at least)
-  qt5_add_resources(CGAL_Qt5_RESOURCE_FILES ./Periodic_2_triangulation_2.qrc)
+  qt6_add_resources(CGAL_Qt6_RESOURCE_FILES ./Periodic_2_triangulation_2.qrc)
 
   # find header files for projects that can show them
   file(GLOB headers "*.h")
@@ -39,8 +39,8 @@ if(CGAL_Qt5_FOUND AND Qt5_FOUND)
     Periodic_2_Delaunay_triangulation_2
     Periodic_2_Delaunay_triangulation_2.cpp
     ${DT_UI_FILES}
-    ${CGAL_Qt5_RESOURCE_FILES}
-    ${CGAL_Qt5_MOC_FILES}
+    ${CGAL_Qt6_RESOURCE_FILES}
+    ${CGAL_Qt6_MOC_FILES}
     ${headers}
     ${QT_headers}
     ${P2T2_headers})
@@ -49,12 +49,12 @@ if(CGAL_Qt5_FOUND AND Qt5_FOUND)
                      Periodic_2_Delaunay_triangulation_2)
 
   target_link_libraries(Periodic_2_Delaunay_triangulation_2
-                        PRIVATE CGAL::CGAL CGAL::CGAL_Qt5 Qt5::Gui)
+                        PRIVATE CGAL::CGAL CGAL::CGAL_Qt6 Qt6::Gui)
 
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(Periodic_2_Delaunay_triangulation_2)
 else()
 
-  message("NOTICE: This demo requires CGAL and Qt5, and will not be compiled.")
+  message("NOTICE: This demo requires CGAL and Qt6, and will not be compiled.")
 
 endif()
diff --git a/GraphicsView/demo/Polygon/CMakeLists.txt b/GraphicsView/demo/Polygon/CMakeLists.txt
index 8314d618d2f..fb753dccefe 100644
--- a/GraphicsView/demo/Polygon/CMakeLists.txt
+++ b/GraphicsView/demo/Polygon/CMakeLists.txt
@@ -13,7 +13,7 @@ if(POLICY CMP0071)
   cmake_policy(SET CMP0071 NEW)
 endif()
 
-find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt5 Core)
+find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt6 Core)
 
 find_package(Eigen3 3.1.0 QUIET) #(requires 3.1.0 or greater)
 include(CGAL_Eigen3_support)
@@ -22,9 +22,9 @@ if(NOT TARGET CGAL::Eigen3_support)
   return()
 endif()
 
-find_package(Qt5 QUIET COMPONENTS Script OpenGL Svg)
+find_package(Qt6 QUIET COMPONENTS OpenGLWidgets Svg)
 
-if(CGAL_Qt5_FOUND AND Qt5_FOUND)
+if(CGAL_Qt6_FOUND AND Qt6_FOUND)
   include(${CGAL_USE_FILE})
   add_definitions(-DQT_NO_KEYWORDS)
   set(CMAKE_AUTOMOC ON)
@@ -34,25 +34,25 @@ if(CGAL_Qt5_FOUND AND Qt5_FOUND)
   endif()
 
   # UI files (Qt Designer files)
-  qt5_wrap_ui(DT_UI_FILES Polygon_2.ui)
+  qt6_wrap_ui(DT_UI_FILES Polygon_2.ui)
 
   # qrc files (resources files, that contain icons, at least)
-  qt5_add_resources(CGAL_Qt5_RESOURCE_FILES ./Polygon_2.qrc)
+  qt6_add_resources(CGAL_Qt6_RESOURCE_FILES ./Polygon_2.qrc)
 
   #  add_library( CGAL SHARED IMPORTED )
   #  SET_PROPERTY(TARGET CGAL PROPERTY IMPORTED_LOCATION ${CGAL_LIBRARY} )
 
   # The executable itself.
   add_executable(Polygon_2 Polygon_2.cpp ${DT_UI_FILES} ${DT_RESOURCE_FILES}
-                           ${CGAL_Qt5_RESOURCE_FILES} ${CGAL_Qt5_MOC_FILES})
+                           ${CGAL_Qt6_RESOURCE_FILES} ${CGAL_Qt6_MOC_FILES})
 
   add_to_cached_list(CGAL_EXECUTABLE_TARGETS Polygon_2)
 
-  target_link_libraries(Polygon_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt5
-                                          CGAL::Eigen3_support Qt5::Gui)
+  target_link_libraries(Polygon_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt6
+                                          CGAL::Eigen3_support Qt6::Gui)
 
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(Polygon_2)
 else()
-  message("NOTICE: This demo requires CGAL, CGAL_Core, and Qt5, and will not be compiled.")
+  message("NOTICE: This demo requires CGAL, CGAL_Core, and Qt6, and will not be compiled.")
 endif()
diff --git a/GraphicsView/demo/Segment_Delaunay_graph_2/CMakeLists.txt b/GraphicsView/demo/Segment_Delaunay_graph_2/CMakeLists.txt
index 745fbb09ed0..653619eb320 100644
--- a/GraphicsView/demo/Segment_Delaunay_graph_2/CMakeLists.txt
+++ b/GraphicsView/demo/Segment_Delaunay_graph_2/CMakeLists.txt
@@ -13,40 +13,36 @@ if(POLICY CMP0071)
   cmake_policy(SET CMP0071 NEW)
 endif()
 
-find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt5 Core)
+find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt6 Core)
 
-set(QT_USE_QTXML TRUE)
-set(QT_USE_QTMAIN TRUE)
-set(QT_USE_QTSCRIPT TRUE)
-set(QT_USE_QTOPENGL TRUE)
 
-find_package(Qt5 QUIET COMPONENTS Script OpenGL Svg)
+find_package(Qt6 QUIET COMPONENTS OpenGLWidgets Svg)
 include_directories(BEFORE ./include)
 
-if(CGAL_Qt5_FOUND AND Qt5_FOUND)
+if(CGAL_Qt6_FOUND AND Qt6_FOUND)
   set(CMAKE_AUTOMOC ON)
 
   include(${CGAL_USE_FILE})
   add_definitions(-DQT_NO_KEYWORDS)
 
   # UI files (Qt Designer files)
-  qt5_wrap_ui(CDT_UI_FILES Segment_voronoi_2.ui)
+  qt6_wrap_ui(CDT_UI_FILES Segment_voronoi_2.ui)
 
   # qrc files (resources files, that contain icons, at least)
-  qt5_add_resources(CGAL_Qt5_RESOURCE_FILES ./Segment_voronoi_2.qrc)
+  qt6_add_resources(CGAL_Qt6_RESOURCE_FILES ./Segment_voronoi_2.qrc)
 
   # The executable itself.
   add_executable(
     Segment_voronoi_2 Segment_voronoi_2.cpp ${CDT_UI_FILES}
-                      ${CGAL_Qt5_RESOURCE_FILES} ${CGAL_Qt5_MOC_FILES})
+                      ${CGAL_Qt6_RESOURCE_FILES} ${CGAL_Qt6_MOC_FILES})
 
   add_to_cached_list(CGAL_EXECUTABLE_TARGETS Segment_voronoi_2)
 
-  target_link_libraries(Segment_voronoi_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt5
-                                                  Qt5::Gui)
+  target_link_libraries(Segment_voronoi_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt6
+                                                  Qt6::Gui)
 
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(Segment_voronoi_2)
 else()
-  message("NOTICE: This demo requires CGAL and Qt5, and will not be compiled.")
+  message("NOTICE: This demo requires CGAL and Qt6, and will not be compiled.")
 endif()
diff --git a/GraphicsView/demo/Segment_Delaunay_graph_Linf_2/CMakeLists.txt b/GraphicsView/demo/Segment_Delaunay_graph_Linf_2/CMakeLists.txt
index f1d5e4fbbd4..25cc1e2f3b6 100644
--- a/GraphicsView/demo/Segment_Delaunay_graph_Linf_2/CMakeLists.txt
+++ b/GraphicsView/demo/Segment_Delaunay_graph_Linf_2/CMakeLists.txt
@@ -13,39 +13,39 @@ if(POLICY CMP0071)
   cmake_policy(SET CMP0071 NEW)
 endif()
 
-find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt5 Core)
+find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt6 Core)
 
 set(QT_USE_QTXML TRUE)
 set(QT_USE_QTMAIN TRUE)
 set(QT_USE_QTSCRIPT TRUE)
 set(QT_USE_QTOPENGL TRUE)
 
-find_package(Qt5 QUIET COMPONENTS Script OpenGL Svg)
+find_package(Qt6 QUIET COMPONENTS OpenGLWidgets Svg)
 include_directories(BEFORE ./include)
 
-if(CGAL_Qt5_FOUND AND Qt5_FOUND)
+if(CGAL_Qt6_FOUND AND Qt6_FOUND)
   set(CMAKE_AUTOMOC ON)
   include(${CGAL_USE_FILE})
   add_definitions(-DQT_NO_KEYWORDS)
 
   # UI files (Qt Designer files)
-  qt5_wrap_ui(CDT_UI_FILES Segment_voronoi_2.ui)
+  qt6_wrap_ui(CDT_UI_FILES Segment_voronoi_2.ui)
 
   # qrc files (resources files, that contain icons, at least)
-  qt5_add_resources(CGAL_Qt5_RESOURCE_FILES ./Segment_voronoi_2.qrc)
+  qt6_add_resources(CGAL_Qt6_RESOURCE_FILES ./Segment_voronoi_2.qrc)
 
   # The executable itself.
   add_executable(
     Segment_voronoi_linf_2 Segment_voronoi_linf_2.cpp ${CDT_UI_FILES}
-                           ${CGAL_Qt5_RESOURCE_FILES} ${CGAL_Qt5_MOC_FILES})
+                           ${CGAL_Qt6_RESOURCE_FILES} ${CGAL_Qt6_MOC_FILES})
 
   add_to_cached_list(CGAL_EXECUTABLE_TARGETS Segment_voronoi_linf_2)
 
   target_link_libraries(Segment_voronoi_linf_2 PRIVATE CGAL::CGAL
-                                                       CGAL::CGAL_Qt5 Qt5::Gui)
+                                                       CGAL::CGAL_Qt6 Qt6::Gui)
 
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(Segment_voronoi_linf_2)
 else()
-  message("NOTICE: This demo requires CGAL and Qt5, and will not be compiled.")
+  message("NOTICE: This demo requires CGAL and Qt6, and will not be compiled.")
 endif()
diff --git a/GraphicsView/demo/Snap_rounding_2/CMakeLists.txt b/GraphicsView/demo/Snap_rounding_2/CMakeLists.txt
index 0b7ebdeb6d8..aaffe63198b 100644
--- a/GraphicsView/demo/Snap_rounding_2/CMakeLists.txt
+++ b/GraphicsView/demo/Snap_rounding_2/CMakeLists.txt
@@ -13,30 +13,30 @@ if(POLICY CMP0071)
   cmake_policy(SET CMP0071 NEW)
 endif()
 
-find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt5)
+find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt6)
 
-find_package(Qt5 QUIET COMPONENTS Script OpenGL Svg)
+find_package(Qt6 QUIET COMPONENTS OpenGLWidgets Svg)
 
-if(CGAL_Qt5_FOUND AND Qt5_FOUND)
+if(CGAL_Qt6_FOUND AND Qt6_FOUND)
   set(CMAKE_AUTOMOC ON)
   add_definitions(-DQT_NO_KEYWORDS)
   set(CMAKE_INCLUDE_CURRENT_DIR ON)
 
   # UI files (Qt Designer files)
-  qt5_wrap_ui(DT_UI_FILES Snap_rounding_2.ui)
+  qt6_wrap_ui(DT_UI_FILES Snap_rounding_2.ui)
 
   # qrc files (resources files, that contain icons, at least)
-  qt5_add_resources(CGAL_Qt5_RESOURCE_FILES ./Snap_rounding_2.qrc)
+  qt6_add_resources(CGAL_Qt6_RESOURCE_FILES ./Snap_rounding_2.qrc)
 
   # The executable itself.
   add_executable(
     Snap_rounding_2 Snap_rounding_2.cpp ${DT_UI_FILES}
-                    ${CGAL_Qt5_RESOURCE_FILES} ${CGAL_Qt5_MOC_FILES})
+                    ${CGAL_Qt6_RESOURCE_FILES} ${CGAL_Qt6_MOC_FILES})
 
   add_to_cached_list(CGAL_EXECUTABLE_TARGETS Snap_rounding_2)
 
-  target_link_libraries(Snap_rounding_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt5
-                                                Qt5::Gui)
+  target_link_libraries(Snap_rounding_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt6
+                                                Qt6::Gui)
 
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(Snap_rounding_2)
@@ -44,5 +44,5 @@ if(CGAL_Qt5_FOUND AND Qt5_FOUND)
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(Snap_rounding_2)
 else()
-  message("NOTICE: This demo requires CGAL and Qt5, and will not be compiled.")
+  message("NOTICE: This demo requires CGAL and Qt6<, and will not be compiled.")
 endif()
diff --git a/GraphicsView/demo/Spatial_searching_2/CMakeLists.txt b/GraphicsView/demo/Spatial_searching_2/CMakeLists.txt
index f5d5aad6d14..6615bea349d 100644
--- a/GraphicsView/demo/Spatial_searching_2/CMakeLists.txt
+++ b/GraphicsView/demo/Spatial_searching_2/CMakeLists.txt
@@ -13,36 +13,36 @@ if(POLICY CMP0071)
   cmake_policy(SET CMP0071 NEW)
 endif()
 
-find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt5)
+find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt6)
 
-find_package(Qt5 QUIET COMPONENTS Script OpenGL Svg)
+find_package(Qt6 QUIET COMPONENTS OpenGLWidgets Svg)
 
-if(CGAL_Qt5_FOUND AND Qt5_FOUND)
+if(CGAL_Qt6_FOUND AND Qt6_FOUND)
 
   add_definitions(-DQT_NO_KEYWORDS)
   set(CMAKE_INCLUDE_CURRENT_DIR ON)
   set(CMAKE_AUTOMOC ON)
 
   # UI files (Qt Designer files)
-  qt5_wrap_ui(DT_UI_FILES Spatial_searching_2.ui)
+  qt6_wrap_ui(DT_UI_FILES Spatial_searching_2.ui)
 
   # qrc files (resources files, that contain icons, at least)
-  qt5_add_resources(CGAL_Qt5_RESOURCE_FILES ./Spatial_searching_2.qrc)
+  qt6_add_resources(CGAL_Qt6_RESOURCE_FILES ./Spatial_searching_2.qrc)
 
   # The executable itself.
   add_executable(
     Spatial_searching_2 Spatial_searching_2.cpp ${DT_UI_FILES}
-                        ${CGAL_Qt5_RESOURCE_FILES} ${CGAL_Qt5_MOC_FILES})
+                        ${CGAL_Qt6_RESOURCE_FILES} ${CGAL_Qt6_MOC_FILES})
 
   add_to_cached_list(CGAL_EXECUTABLE_TARGETS Spatial_searching_2)
 
-  target_link_libraries(Spatial_searching_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt5
-                                                    Qt5::Gui)
+  target_link_libraries(Spatial_searching_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt6
+                                                    Qt6::Gui)
 
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(Spatial_searching_2)
 else()
 
-  message("NOTICE: This demo requires CGAL and Qt5, and will not be compiled.")
+  message("NOTICE: This demo requires CGAL and Qt6, and will not be compiled.")
 
 endif()
diff --git a/GraphicsView/demo/Stream_lines_2/CMakeLists.txt b/GraphicsView/demo/Stream_lines_2/CMakeLists.txt
index 0067351b4e1..19f88273a04 100644
--- a/GraphicsView/demo/Stream_lines_2/CMakeLists.txt
+++ b/GraphicsView/demo/Stream_lines_2/CMakeLists.txt
@@ -13,31 +13,31 @@ if(POLICY CMP0071)
   cmake_policy(SET CMP0071 NEW)
 endif()
 
-find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt5)
+find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt6)
 
-find_package(Qt5 QUIET COMPONENTS Script OpenGL Svg)
+find_package(Qt6 QUIET COMPONENTS OpenGLWidgets Svg)
 
-if(CGAL_Qt5_FOUND AND Qt5_FOUND)
+if(CGAL_Qt6_FOUND AND Qt6_FOUND)
 
   add_definitions(-DQT_NO_KEYWORDS)
   set(CMAKE_INCLUDE_CURRENT_DIR ON)
   set(CMAKE_AUTOMOC ON)
 
   # UI files (Qt Designer files)
-  qt5_wrap_ui(DT_UI_FILES Stream_lines_2.ui)
+  qt6_wrap_ui(DT_UI_FILES Stream_lines_2.ui)
 
   # qrc files (resources files, that contain icons, at least)
-  qt5_add_resources(CGAL_Qt5_RESOURCE_FILES ./Stream_lines_2.qrc)
+  qt6_add_resources(CGAL_Qt6_RESOURCE_FILES ./Stream_lines_2.qrc)
 
   # The executable itself.
   add_executable(
-    Stream_lines_2 Stream_lines_2.cpp ${DT_UI_FILES} ${CGAL_Qt5_RESOURCE_FILES}
-                   ${CGAL_Qt5_MOC_FILES})
+    Stream_lines_2 Stream_lines_2.cpp ${DT_UI_FILES} ${CGAL_Qt6_RESOURCE_FILES}
+                   ${CGAL_Qt6_MOC_FILES})
 
   add_to_cached_list(CGAL_EXECUTABLE_TARGETS Stream_lines_2)
 
-  target_link_libraries(Stream_lines_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt5
-                                               Qt5::Gui)
+  target_link_libraries(Stream_lines_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt6
+                                               Qt6::Gui)
 
   include(${CGAL_MODULES_DIR}/CGAL_add_test.cmake)
   cgal_add_compilation_test(Stream_lines_2)
@@ -47,6 +47,6 @@ if(CGAL_Qt5_FOUND AND Qt5_FOUND)
 
 else()
 
-  message("NOTICE: This demo requires CGAL and Qt5, and will not be compiled.")
+  message("NOTICE: This demo requires CGAL and Qt6, and will not be compiled.")
 
 endif()
diff --git a/GraphicsView/demo/Triangulation_2/CMakeLists.txt b/GraphicsView/demo/Triangulation_2/CMakeLists.txt
index 4560bc339dc..6ee55850f86 100644
--- a/GraphicsView/demo/Triangulation_2/CMakeLists.txt
+++ b/GraphicsView/demo/Triangulation_2/CMakeLists.txt
@@ -16,11 +16,11 @@ endif()
 set(CMAKE_AUTOMOC TRUE)
 set(CMAKE_INCLUDE_CURRENT_DIR TRUE)
 
-find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt5)
-find_package(Qt5 QUIET COMPONENTS Widgets)
+find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt6)
+find_package(Qt6 QUIET COMPONENTS Widgets)
 
-if(NOT CGAL_Qt5_FOUND OR NOT Qt5_FOUND)
-  message("NOTICE: This demo requires CGAL and Qt5, and will not be compiled.")
+if(NOT CGAL_Qt6_FOUND OR NOT Qt6_FOUND)
+  message("NOTICE: This demo requires CGAL and Qt6, and will not be compiled.")
   return()
 endif()
 
@@ -31,15 +31,15 @@ set(CMAKE_INCLUDE_CURRENT_DIR ON)
 # The "constrained Delaunay" demo: Constrained_Delaunay_triangulation_2
 #--------------------------------
 
-qt5_add_resources(CD_RES_FILE Constrained_Delaunay_triangulation_2.qrc)
-qt5_wrap_ui(CD_UI_FILES Constrained_Delaunay_triangulation_2.ui)
+qt6_add_resources(CD_RES_FILE Constrained_Delaunay_triangulation_2.qrc)
+qt6_wrap_ui(CD_UI_FILES Constrained_Delaunay_triangulation_2.ui)
 # The executable itself.
 add_executable(
   Constrained_Delaunay_triangulation_2
   Constrained_Delaunay_triangulation_2.cpp ${CD_UI_FILES}
-  ${CGAL_Qt5_RESOURCE_FILES} ${CD_RES_FILE})
+  ${CGAL_Qt6_RESOURCE_FILES} ${CD_RES_FILE})
 target_link_libraries(Constrained_Delaunay_triangulation_2
-                      PRIVATE CGAL::CGAL CGAL::CGAL_Qt5 Qt5::Widgets)
+                      PRIVATE CGAL::CGAL CGAL::CGAL_Qt6 Qt6::Widgets)
 target_include_directories(Constrained_Delaunay_triangulation_2
                            PRIVATE ./include)
 
@@ -48,14 +48,14 @@ add_to_cached_list(CGAL_EXECUTABLE_TARGETS Constrained_Delaunay_triangulation_2)
 #--------------------------------
 # The "Delaunay" demo: Delaunay_triangulation_2
 #--------------------------------
-qt5_wrap_ui(D_UI_FILES Delaunay_triangulation_2.ui)
-qt5_add_resources(D_RES_FILE Delaunay_triangulation_2.qrc)
+qt6_wrap_ui(D_UI_FILES Delaunay_triangulation_2.ui)
+qt6_add_resources(D_RES_FILE Delaunay_triangulation_2.qrc)
 # The executable itself.
 add_executable(
   Delaunay_triangulation_2 Delaunay_triangulation_2.cpp ${D_UI_FILES}
-                           ${CGAL_Qt5_RESOURCE_FILES} ${D_RES_FILE})
+                           ${CGAL_Qt6_RESOURCE_FILES} ${D_RES_FILE})
 target_link_libraries(Delaunay_triangulation_2
-                      PRIVATE CGAL::CGAL CGAL::CGAL_Qt5 Qt5::Widgets)
+                      PRIVATE CGAL::CGAL CGAL::CGAL_Qt6 Qt6::Widgets)
 
 add_to_cached_list(CGAL_EXECUTABLE_TARGETS Delaunay_triangulation_2)
 
@@ -64,13 +64,13 @@ add_to_cached_list(CGAL_EXECUTABLE_TARGETS Delaunay_triangulation_2)
 #--------------------------------
 
 # The executable itself.
-qt5_add_resources(R_RES_FILE Regular_triangulation_2.qrc)
-qt5_wrap_ui(R_UI_FILES Regular_triangulation_2.ui)
+qt6_add_resources(R_RES_FILE Regular_triangulation_2.qrc)
+qt6_wrap_ui(R_UI_FILES Regular_triangulation_2.ui)
 add_executable(
   Regular_triangulation_2 Regular_triangulation_2.cpp ${R_UI_FILES}
-                          ${CGAL_Qt5_RESOURCE_FILES} ${R_RES_FILE})
-target_link_libraries(Regular_triangulation_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt5
-                                                      Qt5::Widgets)
+                          ${CGAL_Qt6_RESOURCE_FILES} ${R_RES_FILE})
+target_link_libraries(Regular_triangulation_2 PRIVATE CGAL::CGAL CGAL::CGAL_Qt6
+                                                      Qt6::Widgets)
 
 add_to_cached_list(CGAL_EXECUTABLE_TARGETS Regular_triangulation_2)
 
diff --git a/GraphicsView/include/CGAL/Qt/DemosMainWindow_impl.h b/GraphicsView/include/CGAL/Qt/DemosMainWindow_impl.h
index 009b142b963..31458a45eca 100644
--- a/GraphicsView/include/CGAL/Qt/DemosMainWindow_impl.h
+++ b/GraphicsView/include/CGAL/Qt/DemosMainWindow_impl.h
@@ -32,12 +32,11 @@
 #include <QMessageBox>
 #include <QStatusBar>
 #include <QGraphicsView>
-#include <QGLWidget>
+#include <QOpenGLWidget>
 #include <QTextStream>
 #include <QSettings>
 #include <QUrl>
-#include <QDesktopWidget>
-#include <QRegExp>
+#include <QRegularExpression>
 #include <QSvgGenerator>
 #include <QtCore>
 #include <QtOpenGL>
@@ -205,16 +204,16 @@ void
 DemosMainWindow::setUseOpenGL(bool checked)
 {
   if(checked) {
-    QGLWidget* new_viewport = new QGLWidget;
+    // AF QOpenGLWidget* new_viewport = new QOpenGLWidget;
 
     // Setup the format to allow antialiasing with OpenGL:
     // one need to activate the SampleBuffers, if the graphic driver allows
     // this.
-    QGLFormat glformat = new_viewport->format();
-    glformat.setOption(QGL::SampleBuffers);
-    new_viewport->setFormat(glformat);
+    // AF QGLFormat glformat = new_viewport->format();
+    // AF glformat.setOption(QGL::SampleBuffers);
+    // AF new_viewport->setFormat(glformat);
 
-    view->setViewport(new_viewport);
+    // AF view->setViewport(new_viewport);
   }
   else {
     view->setViewport(new QWidget);
diff --git a/GraphicsView/include/CGAL/Qt/qglviewer.h b/GraphicsView/include/CGAL/Qt/qglviewer.h
index 16fd9b123eb..89885041c58 100644
--- a/GraphicsView/include/CGAL/Qt/qglviewer.h
+++ b/GraphicsView/include/CGAL/Qt/qglviewer.h
@@ -30,7 +30,6 @@
 #include <QVector>
 #include <QElapsedTimer>
 #include <QTimer>
-#include <QGLContext>
 #include <QOpenGLWidget>
 #include <QMouseEvent>
 
@@ -72,8 +71,7 @@ class CGAL_QT_EXPORT QGLViewer : public QOpenGLWidget, public QOpenGLFunctions {
 
 public:
   //todo check if this is used. If not remove it
-  explicit QGLViewer(QGLContext* context, QWidget *parent = nullptr,
-                     ::Qt::WindowFlags flags = ::Qt::WindowType(0));
+
   explicit QGLViewer(QOpenGLContext* context, QWidget *parent = nullptr,
                      ::Qt::WindowFlags flags = ::Qt::WindowType(0));
   explicit QGLViewer(QWidget *parent = nullptr,
diff --git a/GraphicsView/include/CGAL/Qt/qglviewer_impl.h b/GraphicsView/include/CGAL/Qt/qglviewer_impl.h
index 0950301c127..d54e88f8aba 100644
--- a/GraphicsView/include/CGAL/Qt/qglviewer_impl.h
+++ b/GraphicsView/include/CGAL/Qt/qglviewer_impl.h
@@ -31,7 +31,7 @@
 #include <QDateTime>
 #include <QDir>
 #include <QFileInfo>
-#include <QGLContext>
+#include <QOpenGLContext>
 #include <QImage>
 #include <QMessageBox>
 #include <QMouseEvent>
diff --git a/Installation/CMakeLists.txt b/Installation/CMakeLists.txt
index 0a521d9dd2c..e4372214dae 100644
--- a/Installation/CMakeLists.txt
+++ b/Installation/CMakeLists.txt
@@ -500,7 +500,7 @@ macro(set_special_prefix library prefix)
   set(CGAL_EXT_LIB_${library}_PREFIX ${prefix})
 endmacro()
 
-set_special_prefix(Qt5 QT)
+set_special_prefix(Qt6 QT)
 set_special_prefix(Eigen3 EIGEN3)
 set_special_prefix(Coin3D COIN3D)
 
@@ -647,10 +647,10 @@ cache_get(CGAL_3RD_PARTY_INCLUDE_DIRS  )
 cache_get(CGAL_3RD_PARTY_LIBRARIES     )
 cache_get(CGAL_3RD_PARTY_LIBRARIES_DIRS)
 
-install(DIRECTORY "${CGAL_GRAPHICSVIEW_PACKAGE_DIR}/include/CGAL/Qt/" DESTINATION "${CGAL_INSTALL_INC_DIR}/CGAL/Qt" COMPONENT CGAL_Qt5)
+install(DIRECTORY "${CGAL_GRAPHICSVIEW_PACKAGE_DIR}/include/CGAL/Qt/" DESTINATION "${CGAL_INSTALL_INC_DIR}/CGAL/Qt" COMPONENT CGAL_Qt6)
 if(CGAL_BRANCH_BUILD)
-  install(DIRECTORY "${CGAL_GRAPHICSVIEW_PACKAGE_DIR}/demo/resources/" DESTINATION "${CGAL_INSTALL_CMAKE_DIR}/demo/resources" COMPONENT CGAL_Qt5)
-  install(DIRECTORY "${CGAL_GRAPHICSVIEW_PACKAGE_DIR}/demo/icons/" DESTINATION "${CGAL_INSTALL_CMAKE_DIR}/demo/icons" COMPONENT CGAL_Qt5)
+  install(DIRECTORY "${CGAL_GRAPHICSVIEW_PACKAGE_DIR}/demo/resources/" DESTINATION "${CGAL_INSTALL_CMAKE_DIR}/demo/resources" COMPONENT CGAL_Qt6)
+  install(DIRECTORY "${CGAL_GRAPHICSVIEW_PACKAGE_DIR}/demo/icons/" DESTINATION "${CGAL_INSTALL_CMAKE_DIR}/demo/icons" COMPONENT CGAL_Qt6)
 endif()
 
 #
@@ -660,7 +660,7 @@ set(CGAL_USE_FILE ${CGAL_MODULES_DIR}/UseCGAL.cmake)
 get_property(CGAL_FOUND GLOBAL PROPERTY CGAL_FOUND)
 get_property(CGAL_Core_FOUND GLOBAL PROPERTY CGAL_Core_FOUND)
 get_property(CGAL_ImageIO_FOUND GLOBAL PROPERTY CGAL_ImageIO_FOUND)
-get_property(CGAL_Qt5_FOUND GLOBAL PROPERTY CGAL_Qt5_FOUND)
+get_property(CGAL_Qt6_FOUND GLOBAL PROPERTY CGAL_Qt6_FOUND)
 
 #
 # Repeat some problems
@@ -928,7 +928,7 @@ if(CGAL_BRANCH_BUILD)
     find_package(GMP REQUIRED)
     find_package(Doxygen REQUIRED)
     find_package(Eigen3 REQUIRED)
-    find_package(Qt5 COMPONENTS Core Widgets OpenGL Gui REQUIRED)
+    find_package(Qt6 COMPONENTS Core Widgets OpenGL Gui REQUIRED)
     find_package(VTK COMPONENTS vtkImagingGeneral vtkIOImage NO_MODULE)
     find_package(IPE)
     find_package(RS3)
@@ -939,10 +939,10 @@ if(CGAL_BRANCH_BUILD)
     set(compile_options
         "\
 ${CMAKE_CXX_FLAGS} -DCGAL_EIGEN3_ENABLED -DCGAL_PROFILE \
-${Qt5Widgets_DEFINITIONS} ${Qt5OpenGL_DEFINITIONS} ${Qt5Gui_DEFINITIONS} \
-${Qt5OpenGL_EXECUTABLE_COMPILE_FLAGS} -fPIC \
-${Qt5Gui_EXECUTABLE_COMPILE_FLAGS} \
-${CGAL_3RD_PARTY_DEFINITIONS} ${CGAL_Qt5_3RD_PARTY_DEFINITIONS} \
+${Qt6Widgets_DEFINITIONS} ${Qt6OpenGL_DEFINITIONS} ${Qt6Gui_DEFINITIONS} \
+${Qt6OpenGL_EXECUTABLE_COMPILE_FLAGS} -fPIC \
+${Qt6Gui_EXECUTABLE_COMPILE_FLAGS} \
+${CGAL_3RD_PARTY_DEFINITIONS} ${CGAL_Qt6_3RD_PARTY_DEFINITIONS} \
 ${CGAL_DEFINITIONS}")
     message("COMPILATION OPTIONS ARE :  ${compile_options}")
 
@@ -1032,11 +1032,11 @@ You must disable CGAL_ENABLE_CHECK_HEADERS.")
       ${RS_INCLUDE_DIR}
       ${EIGEN3_INCLUDE_DIR}
       ${GMP_INCLUDE_DIR}
-      ${Qt5OpenGL_INCLUDE_DIRS}
-      ${Qt5Widgets_INCLUDE_DIRS}
-      ${Qt5Gui_DEFINITIONS}
+      ${Qt6OpenGL_INCLUDE_DIRS}
+      ${Qt6Widgets_INCLUDE_DIRS}
+      ${Qt6Gui_DEFINITIONS}
       ${CGAL_3RD_PARTY_INCLUDE_DIRS}
-      ${CGAL_Qt5_3RD_PARTY_INCLUDE_DIRS})
+      ${CGAL_Qt6_3RD_PARTY_INCLUDE_DIRS})
       list(APPEND include_options "-I${incdir}")
     endforeach()
     include_directories(SYSTEM ${CGAL_3RD_PARTY_INCLUDE_DIRS})
@@ -1234,7 +1234,7 @@ endif()
 
 #print some info about versions
 if(RUNNING_CGAL_AUTO_TEST OR CGAL_TEST_SUITE)
-  find_package(Qt5 QUIET COMPONENTS Core)
+  find_package(Qt6 QUIET COMPONENTS Core)
   find_package(Boost)
   if(NOT CGAL_DISABLE_GMP)
     find_package(GMP)
@@ -1248,7 +1248,7 @@ if(RUNNING_CGAL_AUTO_TEST OR CGAL_TEST_SUITE)
     STATUS
     "USING BOOST_VERSION = '${Boost_MAJOR_VERSION}.${Boost_MINOR_VERSION}.${Boost_SUBMINOR_VERSION}'"
     )
-  if(Qt5_FOUND)
-    message(STATUS "USING Qt5_VERSION = '${Qt5Core_VERSION_STRING}'")
-  endif()#Qt5_FOUND
+  if(Qt6_FOUND)
+    message(STATUS "USING Qt6_VERSION = '${Qt6Core_VERSION_STRING}'")
+  endif()#Qt6_FOUND
 endif()#RUNNING_CGAL_AUTO_TEST OR CGAL_TEST_SUITE
diff --git a/Installation/cmake/modules/CGALConfig_binary.cmake.in b/Installation/cmake/modules/CGALConfig_binary.cmake.in
index b15db42aa7e..7987a2bbd1f 100644
--- a/Installation/cmake/modules/CGALConfig_binary.cmake.in
+++ b/Installation/cmake/modules/CGALConfig_binary.cmake.in
@@ -36,7 +36,7 @@ else()
   CGAL_alias_library(CGAL)
   CGAL_alias_library(CGAL_Core)
   CGAL_alias_library(CGAL_ImageIO)
-  CGAL_alias_library(CGAL_Qt5)
+  CGAL_alias_library(CGAL_Qt6)
 endif()
 
 macro(CGAL_set_LIB_LIBRARY_var lib)
@@ -50,7 +50,7 @@ endmacro()
 CGAL_set_LIB_LIBRARY_var(CGAL)
 CGAL_set_LIB_LIBRARY_var(CGAL_Core)
 CGAL_set_LIB_LIBRARY_var(CGAL_ImageIO)
-CGAL_set_LIB_LIBRARY_var(CGAL_Qt5)
+CGAL_set_LIB_LIBRARY_var(CGAL_Qt6)
 
 set(CGAL_CONFIGURED_LIBRARIES "@CGAL_ACTUAL_CONFIGURED_LIBRARIES@")
 
@@ -120,15 +120,15 @@ macro(check_cgal_component COMPONENT)
   else( "${CGAL_LIB}" STREQUAL "CGAL" )
     if ( WITH_${CGAL_LIB} )
       if(TARGET CGAL::${CGAL_LIB})
-        if ("${CGAL_LIB}" STREQUAL "CGAL_Qt5")
-          
-          include("${CGAL_MODULES_DIR}/CGAL_SetupCGAL_Qt5Dependencies.cmake")
+        if ("${CGAL_LIB}" STREQUAL "CGAL_Qt6")
 
-          if(CGAL_Qt5_MISSING_DEPS)
-            set( CGAL_Qt5_FOUND FALSE )
-            message(STATUS "libCGAL_Qt5 is missing the dependencies: ${CGAL_Qt5_MISSING_DEPS} cannot be configured.")
+          include("${CGAL_MODULES_DIR}/CGAL_SetupCGAL_Qt6Dependencies.cmake")
+
+          if(CGAL_Qt6_MISSING_DEPS)
+            set( CGAL_Qt6_FOUND FALSE )
+            message(STATUS "libCGAL_Qt6 is missing the dependencies: ${CGAL_Qt6_MISSING_DEPS} cannot be configured.")
           else()
-            set( CGAL_Qt5_FOUND TRUE )
+            set( CGAL_Qt6_FOUND TRUE )
           endif()
         elseif("${CGAL_LIB}" STREQUAL "CGAL_Core")
           include("${CGAL_MODULES_DIR}/CGAL_SetupCGAL_CoreDependencies.cmake")
@@ -138,10 +138,10 @@ macro(check_cgal_component COMPONENT)
           else()
             set( CGAL_Core_FOUND TRUE )
           endif()
-        else("${CGAL_LIB}" STREQUAL "CGAL_Qt5")
+        else("${CGAL_LIB}" STREQUAL "CGAL_Qt6")
           # Libraries that have no dependencies
           set( ${CGAL_LIB}_FOUND TRUE )
-        endif("${CGAL_LIB}" STREQUAL "CGAL_Qt5")
+        endif("${CGAL_LIB}" STREQUAL "CGAL_Qt6")
       else(TARGET CGAL::${CGAL_LIB})
         set( ${CGAL_LIB}_FOUND FALSE )
         set( CHECK_${CGAL_LIB}_ERROR_TAIL " CGAL was configured with WITH_${CGAL_LIB}=ON, but one of the dependencies of ${CGAL_LIB} was not configured properly." )
@@ -214,7 +214,7 @@ if (NOT TARGET CGAL::CGAL_Basic_viewer)
   add_library(CGAL::CGAL_Basic_viewer INTERFACE IMPORTED GLOBAL)
     set_target_properties(CGAL::CGAL_Basic_viewer PROPERTIES
       INTERFACE_COMPILE_DEFINITIONS "CGAL_USE_BASIC_VIEWER;QT_NO_KEYWORDS"
-      INTERFACE_LINK_LIBRARIES CGAL::CGAL_Qt5)
+      INTERFACE_LINK_LIBRARIES CGAL::CGAL_Qt6)
 endif()
 
 include("${CGAL_MODULES_DIR}/CGAL_enable_end_of_configuration_hook.cmake")
diff --git a/Installation/cmake/modules/CGALConfig_install.cmake.in b/Installation/cmake/modules/CGALConfig_install.cmake.in
index 00db762aa76..9ee7c0ba880 100644
--- a/Installation/cmake/modules/CGALConfig_install.cmake.in
+++ b/Installation/cmake/modules/CGALConfig_install.cmake.in
@@ -104,15 +104,15 @@ macro(check_cgal_component COMPONENT)
 
     if ( WITH_${CGAL_LIB} )
       if(TARGET CGAL::${CGAL_LIB})
-        if ("${CGAL_LIB}" STREQUAL "CGAL_Qt5")
-          
-          include("${CGAL_MODULES_DIR}/CGAL_SetupCGAL_Qt5Dependencies.cmake")
+        if ("${CGAL_LIB}" STREQUAL "CGAL_Qt6")
 
-          if(CGAL_Qt5_MISSING_DEPS)
-            set( CGAL_Qt5_FOUND FALSE )
-            message(STATUS "libCGAL_Qt5 is missing the dependencies: ${CGAL_Qt5_MISSING_DEPS} cannot be configured.")
+          include("${CGAL_MODULES_DIR}/CGAL_SetupCGAL_Qt6Dependencies.cmake")
+
+          if(CGAL_Qt6_MISSING_DEPS)
+            set( CGAL_Qt6_FOUND FALSE )
+            message(STATUS "libCGAL_Qt6 is missing the dependencies: ${CGAL_Qt6_MISSING_DEPS} cannot be configured.")
           else()
-            set( CGAL_Qt5_FOUND TRUE )
+            set( CGAL_Qt6_FOUND TRUE )
           endif()
         elseif("${CGAL_LIB}" STREQUAL "CGAL_Core")
           include("${CGAL_MODULES_DIR}/CGAL_SetupCGAL_CoreDependencies.cmake")
@@ -122,10 +122,10 @@ macro(check_cgal_component COMPONENT)
           else()
             set( CGAL_Core_FOUND TRUE )
           endif()
-        else("${CGAL_LIB}" STREQUAL "CGAL_Qt5")
+        else("${CGAL_LIB}" STREQUAL "CGAL_Qt6")
           # Libraries that have no dependencies
           set( ${CGAL_LIB}_FOUND TRUE )
-        endif("${CGAL_LIB}" STREQUAL "CGAL_Qt5")
+        endif("${CGAL_LIB}" STREQUAL "CGAL_Qt6")
       else(TARGET CGAL::${CGAL_LIB})
         set( ${CGAL_LIB}_FOUND FALSE )
         set( CHECK_${CGAL_LIB}_ERROR_TAIL " CGAL was configured with WITH_${CGAL_LIB}=ON, but one of the dependencies of ${CGAL_LIB} was not configured properly." )
@@ -198,7 +198,7 @@ if (NOT TARGET CGAL::CGAL_Basic_viewer)
   add_library(CGAL::CGAL_Basic_viewer INTERFACE IMPORTED GLOBAL)
     set_target_properties(CGAL::CGAL_Basic_viewer PROPERTIES
       INTERFACE_COMPILE_DEFINITIONS "CGAL_USE_BASIC_VIEWER;QT_NO_KEYWORDS"
-      INTERFACE_LINK_LIBRARIES CGAL::CGAL_Qt5)
+      INTERFACE_LINK_LIBRARIES CGAL::CGAL_Qt6)
 endif()
 
 include("${CGAL_MODULES_DIR}/CGAL_enable_end_of_configuration_hook.cmake")
diff --git a/Installation/cmake/modules/CGAL_Macros.cmake b/Installation/cmake/modules/CGAL_Macros.cmake
index 8ca618abcd4..2cc35fdc572 100644
--- a/Installation/cmake/modules/CGAL_Macros.cmake
+++ b/Installation/cmake/modules/CGAL_Macros.cmake
@@ -229,7 +229,7 @@ if( NOT CGAL_MACROS_FILE_INCLUDED )
           message (STATUS "Configured ${lib} from UseLIB-file: ${usefile}")
 
           # UseLIB-file has to set ${vlib}_SETUP to TRUE
-          # TODO EBEB what about Qt5, zlib?
+          # TODO EBEB what about Qt6, zlib?
 
         else()
 
@@ -288,11 +288,11 @@ if( NOT CGAL_MACROS_FILE_INCLUDED )
       add_to_list( CGAL_3RD_PARTY_DEFINITIONS    ${CGAL_${component}_3RD_PARTY_DEFINITIONS}    )
       add_to_list( CGAL_3RD_PARTY_LIBRARIES_DIRS ${CGAL_${component}_3RD_PARTY_LIBRARIES_DIRS} )
 
-      # To deal with imported targets of Qt5 and Boost, when CGAL
+      # To deal with imported targets of Qt6 and Boost, when CGAL
       # targets are themselves imported by another project.
 
-      if (${component} STREQUAL "Qt5")
-        find_package(Qt5 COMPONENTS OpenGL Gui Core Script ScriptTools QUIET)
+      if (${component} STREQUAL "Qt6")
+        find_package(Qt6 COMPONENTS Widgets OpenGLWidgets Gui Core Script ScriptTools QUIET)
       endif()
 
     else(WITH_CGAL_${component})
diff --git a/Installation/cmake/modules/CGAL_Qt6_moc_and_resource_files.cmake b/Installation/cmake/modules/CGAL_Qt6_moc_and_resource_files.cmake
index 21b32bc2e9e..c3c6cbb7143 100644
--- a/Installation/cmake/modules/CGAL_Qt6_moc_and_resource_files.cmake
+++ b/Installation/cmake/modules/CGAL_Qt6_moc_and_resource_files.cmake
@@ -4,7 +4,7 @@ endif()
 set(CGAL_Qt6_moc_and_resource_files_included TRUE)
 # qrc files (resources files, that contain icons, at least)
 if(EXISTS ${CGAL_GRAPHICSVIEW_PACKAGE_DIR}/demo/resources/CGAL.qrc)
-  qt5_add_resources (_CGAL_Qt6_RESOURCE_FILES_private
+  qt6_add_resources (_CGAL_Qt6_RESOURCE_FILES_private
     ${CGAL_GRAPHICSVIEW_PACKAGE_DIR}/demo/resources/CGAL.qrc
     ${CGAL_GRAPHICSVIEW_PACKAGE_DIR}/demo/icons/Input.qrc
     ${CGAL_GRAPHICSVIEW_PACKAGE_DIR}/demo/icons/File.qrc
@@ -15,11 +15,11 @@ else()
     ${CGAL_MODULES_DIR}/demo/resources
     ${CGAL_MODULES_DIR}/demo/icons
     DESTINATION ${CMAKE_BINARY_DIR})
-  qt5_add_resources (_CGAL_Qt6_RESOURCE_FILES_private
+  qt6_add_resources (_CGAL_Qt6_RESOURCE_FILES_private
     ${CMAKE_BINARY_DIR}/resources/CGAL.qrc
     ${CMAKE_BINARY_DIR}/icons/Input.qrc
     ${CMAKE_BINARY_DIR}/icons/File.qrc
     ${CMAKE_BINARY_DIR}/icons/Triangulation_2.qrc)
 endif()
 
-qt5_wrap_ui(_CGAL_Qt6_UI_FILES ${CGAL_GRAPHICSVIEW_PACKAGE_DIR}/include/CGAL/Qt/ImageInterface.ui)
+qt_wrap_ui(_CGAL_Qt6_UI_FILES ${CGAL_GRAPHICSVIEW_PACKAGE_DIR}/include/CGAL/Qt/ImageInterface.ui)
diff --git a/Installation/cmake/modules/CGAL_SetupCGAL_Qt6Dependencies.cmake b/Installation/cmake/modules/CGAL_SetupCGAL_Qt6Dependencies.cmake
index 161e9673345..690d018d33f 100644
--- a/Installation/cmake/modules/CGAL_SetupCGAL_Qt6Dependencies.cmake
+++ b/Installation/cmake/modules/CGAL_SetupCGAL_Qt6Dependencies.cmake
@@ -9,7 +9,7 @@
 #
 # .. code-block:: cmake
 #
-#    find_package(Qt6 QUIET COMPONENTS OpenGL Svg)
+#    find_package(Qt6 QUIET COMPONENTS OpenGLWidgets Svg)
 #
 # and defines the variable :variable:`CGAL_Qt6_FOUND` and the function
 # :command:`CGAL_setup_CGAL_Qt6_dependencies`.
@@ -24,19 +24,24 @@ set(CGAL_SetupCGAL_Qt6Dependencies_included TRUE)
 # Used Modules
 # ^^^^^^^^^^^^
 #   - :module:`Qt6Config`
-find_package(Qt6 QUIET COMPONENTS OpenGL Svg)
+
+find_package(Qt6 QUIET COMPONENTS Widgets OpenGLWidgets Svg)
 
 set(CGAL_Qt6_MISSING_DEPS "")
-if(NOT Qt6OpenGL_FOUND)
-  set(CGAL_Qt6_MISSING_DEPS "Qt6OpenGL")
+if(NOT Qt6OpenGLWidgets_FOUND)
+  message( STATUS "NOTICE: NOT Qt6OpenGLWidgets_FOUND")
+  set(CGAL_Qt6_MISSING_DEPS "Qt6OpenGLWidgets")
 endif()
 if(NOT Qt6Svg_FOUND)
+  message(STATUS "NOTICE: NOT Qt6Svg_FOUND")
   set(CGAL_Qt6_MISSING_DEPS "${CGAL_Qt6_MISSING_DEPS} Qt6Svg")
 endif()
 if(NOT Qt6_FOUND)
+  message(STATUS "NOTICE: NOT Qt6_FOUND")
   set(CGAL_Qt6_MISSING_DEPS "${CGAL_Qt6_MISSING_DEPS} Qt6")
 endif()
 if(NOT EXISTS ${CGAL_GRAPHICSVIEW_PACKAGE_DIR}/include/CGAL/Qt/GraphicsItem.h)
+  message(STATUS "NOTICE: NOT EXISTS GraphicsItem")
   set(CGAL_Qt6_MISSING_DEPS "${CGAL_Qt6_MISSING_DEPS} <CGAL/Qt/*.h> headers")
 endif()
 
@@ -75,7 +80,7 @@ if(NOT CGAL_Qt6_MISSING_DEPS)
       POSITION_INDEPENDENT_CODE TRUE
       EXCLUDE_FROM_ALL TRUE
       AUTOMOC TRUE)
-    target_link_libraries(CGAL_Qt6_moc_and_resources CGAL::CGAL Qt6::Widgets Qt6::OpenGL Qt6::Svg )
+    target_link_libraries(CGAL_Qt6_moc_and_resources CGAL::CGAL Qt6::Widgets Qt6::OpenGLWidgets Qt6::Svg )
 
     add_library(CGAL::CGAL_Qt6_moc_and_resources ALIAS CGAL_Qt6_moc_and_resources)
     add_library(CGAL::Qt6_moc_and_resources ALIAS CGAL_Qt6_moc_and_resources)
@@ -112,7 +117,7 @@ function(CGAL_setup_CGAL_Qt6_dependencies target)
   endif()
   target_link_libraries( ${target} INTERFACE CGAL::CGAL)
   target_link_libraries( ${target} INTERFACE CGAL::Qt6_moc_and_resources)
-  target_link_libraries( ${target} INTERFACE Qt6::OpenGL Qt6::Svg )
+  target_link_libraries( ${target} INTERFACE Qt6::OpenGLWidgets Qt6::Svg )
 
   # Remove -Wdeprecated-copy, for g++ >= 9.0, because Qt6, as of
   # version 5.12, has a lot of [-Wdeprecated-copy] warnings.
diff --git a/Installation/cmake/modules/CGAL_add_test.cmake b/Installation/cmake/modules/CGAL_add_test.cmake
index a5c8b2bc83a..eb0c748109c 100644
--- a/Installation/cmake/modules/CGAL_add_test.cmake
+++ b/Installation/cmake/modules/CGAL_add_test.cmake
@@ -117,23 +117,23 @@ function(cgal_add_compilation_test exe_name)
     set_property(TEST "check_build_system"
        PROPERTY FIXTURES_SETUP "check_build_system_SetupFixture")
   endif()
-  if(TARGET CGAL_Qt5_moc_and_resources) # if CGAL_Qt5 was searched, and is header-only
+  if(TARGET CGAL_Qt6_moc_and_resources) # if CGAL_Qt6 was searched, and is header-only
     get_property(linked_libraries TARGET "${exe_name}" PROPERTY LINK_LIBRARIES)
     #  message(STATUS "${exe_name} depends on ${linked_libraries}")
-    string(FIND "${linked_libraries}" "CGAL::CGAL_Qt5" link_with_CGAL_Qt5)
-    if(link_with_CGAL_Qt5 STRGREATER "-1" AND
-        NOT TARGET compilation_of__CGAL_Qt5_moc_and_resources)
+    string(FIND "${linked_libraries}" "CGAL::CGAL_Qt6" link_with_CGAL_Qt6)
+    if(link_with_CGAL_Qt6 STRGREATER "-1" AND
+        NOT TARGET compilation_of__CGAL_Qt6_moc_and_resources)
       # This custom target is useless. It is used only as a flag to
       # detect that the test has already been created.
-      add_custom_target(compilation_of__CGAL_Qt5_moc_and_resources)
-      add_dependencies( compilation_of__CGAL_Qt5_moc_and_resources CGAL_Qt5_moc_and_resources )
-      add_test(NAME "compilation_of__CGAL_Qt5_moc_and_resources"
-        COMMAND "${CMAKE_COMMAND}" --build "${CMAKE_BINARY_DIR}" --target "CGAL_Qt5_moc_and_resources" --config "$<CONFIG>")
-      set_property(TEST "compilation_of__CGAL_Qt5_moc_and_resources"
+      add_custom_target(compilation_of__CGAL_Qt6_moc_and_resources)
+      add_dependencies( compilation_of__CGAL_Qt6_moc_and_resources CGAL_Qt6_moc_and_resources )
+      add_test(NAME "compilation_of__CGAL_Qt6_moc_and_resources"
+        COMMAND "${CMAKE_COMMAND}" --build "${CMAKE_BINARY_DIR}" --target "CGAL_Qt6_moc_and_resources" --config "$<CONFIG>")
+      set_property(TEST "compilation_of__CGAL_Qt6_moc_and_resources"
         APPEND PROPERTY LABELS "CGAL_build_system")
-      set_property(TEST "compilation_of__CGAL_Qt5_moc_and_resources"
-        PROPERTY FIXTURES_SETUP "CGAL_Qt5_moc_and_resources_Fixture")
-      set_property(TEST "compilation_of__CGAL_Qt5_moc_and_resources"
+      set_property(TEST "compilation_of__CGAL_Qt6_moc_and_resources"
+        PROPERTY FIXTURES_SETUP "CGAL_Qt6_moc_and_resources_Fixture")
+      set_property(TEST "compilation_of__CGAL_Qt6_moc_and_resources"
         APPEND PROPERTY DEPENDS "check_build_system")
     endif()
   endif()
@@ -313,7 +313,7 @@ function(cgal_add_test exe_name)
         -P "${CGAL_MODULES_DIR}/run_test_with_cin.cmake")
       set_property(DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
         APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS ${cin_file})
-      #	message(STATUS "add test: ${exe_name} < ${cin_file}")
+      # message(STATUS "add test: ${exe_name} < ${cin_file}")
     endif()
   else()
     if(NOT ARGS AND NOT cgal_add_test_TEST_NAME)
@@ -328,12 +328,12 @@ function(cgal_add_test exe_name)
         file(STRINGS "${cmd_file}" CMD_LINES)
         string(CONFIGURE "${CMD_LINES}" CMD_LINES)
         set(ARGS)
-        #	  message(STATUS "DEBUG test ${exe_name}")
+        #         message(STATUS "DEBUG test ${exe_name}")
         foreach(CMD_LINE ${CMD_LINES})
-    #	    message(STATUS "  command line: ${CMD_LINE}")
+    #       message(STATUS "  command line: ${CMD_LINE}")
           string(REGEX REPLACE "\#.*" "" CMD_LINE "${CMD_LINE}")
           separate_arguments(CMD_LINE_ARGS UNIX_COMMAND ${CMD_LINE})
-    #	    message(STATUS "  args: ${CMD_LINE_ARGS}")
+    #       message(STATUS "  args: ${CMD_LINE_ARGS}")
           list(APPEND ARGS ${CMD_LINE_ARGS})
         endforeach()
         expand_list_with_globbing(ARGS)
@@ -341,7 +341,7 @@ function(cgal_add_test exe_name)
           APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS ${cmd_file})
       endif()
     endif()
-    #	message(STATUS "add test: ${exe_name} ${ARGS}")
+    #   message(STATUS "add test: ${exe_name} ${ARGS}")
     if(ANDROID)
       add_test(NAME ${test_name} COMMAND ${TIME_COMMAND} ${adb_executable} shell cd ${CGAL_REMOTE_TEST_DIR_PREFIX}${PROJECT_NAME} && LD_LIBRARY_PATH=${CGAL_REMOTE_TEST_DIR_PREFIX}${PROJECT_NAME} ${CGAL_REMOTE_TEST_DIR_PREFIX}${PROJECT_NAME}/${exe_name} ${ARGS})
     elseif(CGAL_RUN_TESTS_THROUGH_SSH)
diff --git a/Installation/cmake/modules/CGAL_setup_target_dependencies.cmake b/Installation/cmake/modules/CGAL_setup_target_dependencies.cmake
index bed40154c80..820664d0498 100644
--- a/Installation/cmake/modules/CGAL_setup_target_dependencies.cmake
+++ b/Installation/cmake/modules/CGAL_setup_target_dependencies.cmake
@@ -5,7 +5,7 @@ function(CGAL_setup_target_dependencies target)
     CGAL_setup_CGAL_Core_dependencies(${target})
   elseif(${target} STREQUAL CGAL_ImageIO)
     CGAL_setup_CGAL_ImageIO_dependencies(${target})
-  elseif(${target} STREQUAL CGAL_Qt5)
-    CGAL_setup_CGAL_Qt5_dependencies(${target})
+  elseif(${target} STREQUAL CGAL_Qt6)
+    CGAL_setup_CGAL_Qt6_dependencies(${target})
   endif()
 endfunction()
diff --git a/Installation/lib/cmake/CGAL/CGALConfig.cmake b/Installation/lib/cmake/CGAL/CGALConfig.cmake
index b9030ecc4dc..f7afccf0057 100644
--- a/Installation/lib/cmake/CGAL/CGALConfig.cmake
+++ b/Installation/lib/cmake/CGAL/CGALConfig.cmake
@@ -128,7 +128,7 @@ if( CGAL_DEV_MODE OR RUNNING_CGAL_AUTO_TEST OR CGAL_TEST_SUITE )
 endif()
 
 foreach(comp ${CGAL_FIND_COMPONENTS})
-  if(NOT comp MATCHES "Core|ImageIO|Qt5")
+  if(NOT comp MATCHES "Core|ImageIO|Qt6")
     message(FATAL_ERROR "The requested CGAL component ${comp} does not exist!")
   endif()
   if(comp MATCHES "Core" AND CGAL_DISABLE_GMP)
@@ -193,6 +193,5 @@ if (NOT TARGET CGAL::CGAL_Basic_viewer)
   add_library(CGAL::CGAL_Basic_viewer INTERFACE IMPORTED GLOBAL)
     set_target_properties(CGAL::CGAL_Basic_viewer PROPERTIES
       INTERFACE_COMPILE_DEFINITIONS "CGAL_USE_BASIC_VIEWER;QT_NO_KEYWORDS"
-      INTERFACE_LINK_LIBRARIES CGAL::CGAL_Qt5)
+      INTERFACE_LINK_LIBRARIES CGAL::CGAL_Qt6)
 endif()
-