diff --git a/cmake/QtBaseGlobalTargets.cmake b/cmake/QtBaseGlobalTargets.cmake
index cf69c1f540d..15d2b887e20 100644
--- a/cmake/QtBaseGlobalTargets.cmake
+++ b/cmake/QtBaseGlobalTargets.cmake
@@ -55,11 +55,21 @@ qt_install(FILES
     DESTINATION "${__build_internals_install_dir}"
     COMPONENT Devel
 )
+
+qt_path_join(__build_internals_standalone_test_template_path
+    "${CMAKE_CURRENT_SOURCE_DIR}"
+    "cmake/QtBuildInternals/${__build_internals_standalone_test_template_dir}")
+
 qt_copy_or_install(
-    DIRECTORY
-    "${CMAKE_CURRENT_SOURCE_DIR}/cmake/QtBuildInternals/${__build_internals_standalone_test_template_dir}"
+    DIRECTORY "${__build_internals_standalone_test_template_path}"
     DESTINATION "${__build_internals_install_dir}")
 
+# In prefix builds we also need to copy the files into the build dir.
+if(QT_WILL_INSTALL)
+    file(COPY "${__build_internals_standalone_test_template_path}"
+        DESTINATION "${__build_internals_install_dir}")
+endif()
+
 set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS
     "${CMAKE_CURRENT_SOURCE_DIR}/cmake/QtBuildInternals/${__build_internals_standalone_test_template_dir}/CMakeLists.txt")
 
diff --git a/cmake/QtBaseHelpers.cmake b/cmake/QtBaseHelpers.cmake
index 0c3cca9dc1c..90d2cf8266f 100644
--- a/cmake/QtBaseHelpers.cmake
+++ b/cmake/QtBaseHelpers.cmake
@@ -137,7 +137,7 @@ macro(qt_internal_qtbase_install_mkspecs)
         LIST_DIRECTORIES TRUE
         "${PROJECT_SOURCE_DIR}/mkspecs/*")
     foreach(entry IN LISTS mkspecs_subdirs)
-        if (IS_DIRECTORY ${entry})
+        if(IS_DIRECTORY ${entry})
             qt_copy_or_install(DIRECTORY "${entry}"
                                DESTINATION ${mkspecs_install_dir}
                                USE_SOURCE_PERMISSIONS)
@@ -145,6 +145,11 @@ macro(qt_internal_qtbase_install_mkspecs)
             qt_copy_or_install(FILES "${entry}"
                                DESTINATION ${mkspecs_install_dir})
         endif()
+
+        # In prefix builds we also need to copy the files into the build dir.
+        if(QT_WILL_INSTALL)
+            file(COPY "${entry}" DESTINATION "${mkspecs_install_dir}")
+        endif()
     endforeach()
 endmacro()