diff --git a/config.h b/config.h
index 0a701a7..8d39173 100644
--- a/config.h
+++ b/config.h
@@ -1,6 +1,8 @@
 #ifndef CONFIG_H
 #define CONFIG_H
 
+#include <stdbool.h>
+
 #define GUARD_SLABS true
 #define WRITE_AFTER_FREE_CHECK true
 #define SLOT_RANDOMIZE true