diff --git a/Makefile.include b/Makefile.include
index 74e9f4db58..6d08a9ad8f 100644
--- a/Makefile.include
+++ b/Makefile.include
@@ -134,6 +134,7 @@ endif
 
 # remove this once codebase is adapted
 CFLAGS += -Wno-implicit-fallthrough
+CXXFLAGS += -Wno-implicit-fallthrough
 
 ifneq (10,$(if ${RIOT_VERSION},1,0)$(if ${__RIOTBUILD_FLAG},1,0))