diff --git a/nshlib/nsh_vars.c b/nshlib/nsh_vars.c
index a56e29035..3a829e378 100644
--- a/nshlib/nsh_vars.c
+++ b/nshlib/nsh_vars.c
@@ -41,6 +41,7 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include <assert.h>
 #include <errno.h>
 
 #include "nsh.h"