diff --git a/core/net/mac/nullrdc.c b/core/net/mac/nullrdc.c
index 04baa90bd..5cec23a3d 100644
--- a/core/net/mac/nullrdc.c
+++ b/core/net/mac/nullrdc.c
@@ -48,6 +48,7 @@
 
 #if CONTIKI_TARGET_COOJA
 #include "lib/simEnvChange.h"
+#include "sys/cooja_mt.h"
 #endif /* CONTIKI_TARGET_COOJA */
 
 #define DEBUG 0