diff --git a/td/telegram/MessageContent.h b/td/telegram/MessageContent.h
index 65d19c517..b4a7105a7 100644
--- a/td/telegram/MessageContent.h
+++ b/td/telegram/MessageContent.h
@@ -32,6 +32,7 @@
 #include "td/utils/common.h"
 #include "td/utils/Status.h"
 
+#include <functional>
 #include <utility>
 
 namespace td {