diff --git a/ros2_foxglove_bridge/src/message_definition_cache.cpp b/ros2_foxglove_bridge/src/message_definition_cache.cpp
index 3d5dcf6..262c482 100644
--- a/ros2_foxglove_bridge/src/message_definition_cache.cpp
+++ b/ros2_foxglove_bridge/src/message_definition_cache.cpp
@@ -2,6 +2,7 @@
 
 #include <filesystem>
 #include <fstream>
+#include <functional>
 #include <optional>
 #include <regex>
 #include <set>