diff --git a/core/thread_flags.c b/core/thread_flags.c
index 479c7c36e9..9396c31e30 100644
--- a/core/thread_flags.c
+++ b/core/thread_flags.c
@@ -19,7 +19,6 @@
  */
 
 
-#include "bitarithm.h"
 #include "thread_flags.h"
 #include "irq.h"
 #include "thread.h"