diff --git a/client/client_state.C b/client/client_state.C
index c7071dfc5e..ae361bfc43 100644
--- a/client/client_state.C
+++ b/client/client_state.C
@@ -39,6 +39,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
+#include <cassert>
 
 #include "parse.h"
 #include "util.h"