diff --git a/include/wampcc/protocol.h b/include/wampcc/protocol.h
index e863768..3c86033 100644
--- a/include/wampcc/protocol.h
+++ b/include/wampcc/protocol.h
@@ -11,6 +11,7 @@
 #include "wampcc/types.h"
 
 #include <vector>
+#include <chrono>
 #include <cstddef>
 #include <memory>
 #include <stdexcept>