diff --git a/cmake/CompileFlags.cmake b/cmake/CompileFlags.cmake
index 9bf15e6b78..691feaed0d 100644
--- a/cmake/CompileFlags.cmake
+++ b/cmake/CompileFlags.cmake
@@ -96,7 +96,10 @@ macro(compile_flags)
 
         if(NOT CMAKE_BUILD_TYPE)
             # Sensible default if no build type specified
-            add_compile_options(-O2 -DNDEBUG)
+            add_compile_options(-O2)
+            if(NOT CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
+                add_compile_options(-DNDEBUG)
+            endif()
         endif(NOT CMAKE_BUILD_TYPE)
 
         # When we are a stable release (Release build + USE_ASSERTS not set),