diff --git a/backends/apple/coreml/CMakeLists.txt b/backends/apple/coreml/CMakeLists.txt
index ca20d3615f..70daed7d06 100644
--- a/backends/apple/coreml/CMakeLists.txt
+++ b/backends/apple/coreml/CMakeLists.txt
@@ -135,7 +135,7 @@ target_include_directories(
 )
 target_include_directories(coremldelegate PRIVATE ${EXECUTORCH_ROOT}/..)
 target_include_directories(coremldelegate PRIVATE ${EXECUTORCH_ROOT}/runtime/core/portable_type)
-target_compile_definitions(coremldelegate C10_USING_CUSTOM_GENERATED_MACROS)
+target_compile_definitions(coremldelegate PRIVATE C10_USING_CUSTOM_GENERATED_MACROS)
 target_link_libraries(coremldelegate PRIVATE executorch_core)
 
 if(EXECUTORCH_BUILD_DEVTOOLS)