diff --git a/src/thread.h b/src/thread.h
index d4ca10c..43bd542 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -19,6 +19,7 @@
 #define ARGON2_THREAD_H
 
 #if !defined(ARGON2_NO_THREADS)
+#include <stdint.h>
 
 /*
         Here we implement an abstraction layer for the simpĺe requirements