diff --git a/quantum/mousekey.c b/quantum/mousekey.c
index 0cbb472045b7..64d0e6668205 100644
--- a/quantum/mousekey.c
+++ b/quantum/mousekey.c
@@ -16,6 +16,7 @@
  */
 
 #include <stdint.h>
+#include <string.h>
 #include "keycode.h"
 #include "host.h"
 #include "timer.h"