diff --git a/cmake/DD4hepBuild.cmake b/cmake/DD4hepBuild.cmake
index 897c5aeef1a15c459692f183f2e7b688465fab49..f8841c803443f486888b49cdb8e874db17db573b 100644
--- a/cmake/DD4hepBuild.cmake
+++ b/cmake/DD4hepBuild.cmake
@@ -41,7 +41,7 @@ macro(dd4hep_set_compiler_flags)
 
   # AppleClang/Clang specific warning flags
   if(CMAKE_CXX_COMPILER_ID MATCHES "^(Apple)?Clang$")
-    set ( COMPILER_FLAGS ${COMPILER_FLAGS} -Winconsistent-missing-override -Wno-c++1z-extensions)
+    set ( COMPILER_FLAGS ${COMPILER_FLAGS} -Winconsistent-missing-override -Wno-c++1z-extensions -Wheader-hygiene )
   endif()
 
   FOREACH( FLAG ${COMPILER_FLAGS} )