diff --git a/googletest/cmake/internal_utils.cmake b/googletest/cmake/internal_utils.cmake
index 580ac1cbc..1bb181cf0 100644
--- a/googletest/cmake/internal_utils.cmake
+++ b/googletest/cmake/internal_utils.cmake
@@ -114,7 +114,7 @@ macro(config_compiler_and_linker)
     # explicitly.
     set(cxx_no_rtti_flags "-fno-rtti -DGTEST_HAS_RTTI=0")
     set(cxx_strict_flags
-      "-Wextra -Wno-unused-parameter -Wno-missing-field-initializers")
+      "-Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wreturn-type -Werror")
   elseif (CMAKE_CXX_COMPILER_ID STREQUAL "SunPro")
     set(cxx_exception_flags "-features=except")
     # Sun Pro doesn't provide macros to indicate whether exceptions and