diff --git a/CMakeLists.txt b/CMakeLists.txt
index aba2ec14dd4..4a0d0ca3027 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -67,7 +67,14 @@ project(
     C
 )
 
-set(ITK_CMAKE_DIR "${ITK_SOURCE_DIR}/CMake")
+# Made a cache variable to be used by project which use FetchContent to build ITK.
+set(
+  ITK_CMAKE_DIR
+  "${ITK_SOURCE_DIR}/CMake"
+  CACHE INTERNAL
+  "Directory containing CMake files for ITK configuration and module macros"
+  FORCE
+)
 
 if(APPLE)
   include(itkApple)