diff --git a/src/t_hash.c b/src/t_hash.c
index fda6d925cb..55dee2e897 100644
--- a/src/t_hash.c
+++ b/src/t_hash.c
@@ -29,6 +29,7 @@
 
 #include "server.h"
 #include <math.h>
+#include <stdbool.h>
 
 /*-----------------------------------------------------------------------------
  * Hash Entry API