diff --git a/xs/src/admesh/stlinit.c b/xs/src/admesh/stlinit.c
index 77b7f9fe5..6efb40ea5 100644
--- a/xs/src/admesh/stlinit.c
+++ b/xs/src/admesh/stlinit.c
@@ -24,6 +24,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <math.h>
+#include <assert.h>
 
 #include "stl.h"