diff --git a/src/base/trie.hh b/src/base/trie.hh
index a5aca2c6fe..e6b2881ab1 100644
--- a/src/base/trie.hh
+++ b/src/base/trie.hh
@@ -31,6 +31,8 @@
 #ifndef __BASE_TRIE_HH__
 #define __BASE_TRIE_HH__
 
+#include <cassert>
+
 #include "base/cprintf.hh"
 #include "base/misc.hh"
 #include "base/types.hh"