diff --git a/src/event_manager.hh b/src/event_manager.hh
index 72245f0d..7edf949d 100644
--- a/src/event_manager.hh
+++ b/src/event_manager.hh
@@ -6,6 +6,7 @@
 
 #include <chrono>
 #include <vector>
+#include <functional>
 
 #include <sys/select.h>