diff --git a/inc/msp/Client.hpp b/inc/msp/Client.hpp
index 1cfbd08..29da27e 100644
--- a/inc/msp/Client.hpp
+++ b/inc/msp/Client.hpp
@@ -3,6 +3,7 @@
 
 #include <string>
 #include <thread>
+#include <mutex>
 #include <condition_variable>
 #include <map>
 #include "types.hpp"