diff --git a/CMakeLists.txt b/CMakeLists.txt
index 50e55f8161..8957e0dc9c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -85,6 +85,11 @@ if(NOT DEFINED IGDRCL_SOURCE_DIR)
   set(IGDRCL_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 endif()
 
+# Set the core source directory
+if(NOT DEFINED NEO_CORE_DIRECTORY)
+  set(NEO_CORE_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/core)
+endif()
+
 if(SKIP_ALL_ULT)
     set(SKIP_UNIT_TESTS TRUE)
 endif()