diff --git a/src/ChunkedEncoding.h b/src/ChunkedEncoding.h
index 9ecffd6e5..05bd0cc1c 100644
--- a/src/ChunkedEncoding.h
+++ b/src/ChunkedEncoding.h
@@ -20,6 +20,7 @@
 
 /* Independent chunked encoding parser, used by HttpParser. */
 
+#include <cstdint>
 #include <string>
 #include <cstring>
 #include <algorithm>