diff --git a/api/include/opentelemetry/trace/propagation/detail/hex.h b/api/include/opentelemetry/trace/propagation/detail/hex.h
index c8bd58f8b8..157f5ec42a 100644
--- a/api/include/opentelemetry/trace/propagation/detail/hex.h
+++ b/api/include/opentelemetry/trace/propagation/detail/hex.h
@@ -4,6 +4,7 @@
 #pragma once
 
 #include <algorithm>
+#include <cstdint>
 #include <cstring>
 
 #include "opentelemetry/nostd/string_view.h"