diff --git a/include/Timer.h b/include/Timer.h
index fca89bd..34b9a82 100644
--- a/include/Timer.h
+++ b/include/Timer.h
@@ -7,6 +7,7 @@
 #include <functional>
 #include <memory>
 #include <mutex>
+#include <string>
 #include <thread>