diff --git a/src/utf.cpp b/src/utf.cpp
index c3b6554..31bed61 100644
--- a/src/utf.cpp
+++ b/src/utf.cpp
@@ -43,6 +43,7 @@
 ------------------------------------------------------------------------ */
 
 #include <iterator>
+#include <cstdint>
 #include <utf/utf.hpp>
 
 namespace utf {