diff --git a/src/tests.c b/src/tests.c
index 305a240e..ccc06c19 100644
--- a/src/tests.c
+++ b/src/tests.c
@@ -11,6 +11,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+#include <time.h>
+
 #include "secp256k1.c"
 #include "testrand_impl.h"