diff --git a/xml_converter/generators/generate_cpp.py b/xml_converter/generators/generate_cpp.py
index b9b86c8d..55e33571 100644
--- a/xml_converter/generators/generate_cpp.py
+++ b/xml_converter/generators/generate_cpp.py
@@ -223,6 +223,7 @@ def generate_cpp_variable_data(
 
     cpp_includes.cpp_absolute_includes.add("iosfwd")
     cpp_includes.cpp_absolute_includes.add("string")
+    cpp_includes.hpp_absolute_includes.add("functional")
     cpp_includes.cpp_relative_includes.add("rapidxml-1.13/rapidxml.hpp")
     cpp_includes.cpp_relative_includes.add("string_helper.hpp")
     cpp_includes.cpp_relative_includes.add("rapid_helpers.hpp")
diff --git a/xml_converter/src/category_gen.hpp b/xml_converter/src/category_gen.hpp
index 3ef42874..8f51ea43 100644
--- a/xml_converter/src/category_gen.hpp
+++ b/xml_converter/src/category_gen.hpp
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <functional>
 #include <map>
 #include <string>
 #include <vector>
diff --git a/xml_converter/src/icon_gen.hpp b/xml_converter/src/icon_gen.hpp
index 771b72fa..d0f66677 100644
--- a/xml_converter/src/icon_gen.hpp
+++ b/xml_converter/src/icon_gen.hpp
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <functional>
 #include <string>
 #include <vector>
 
diff --git a/xml_converter/src/trail_gen.hpp b/xml_converter/src/trail_gen.hpp
index d2a5d488..a681494e 100644
--- a/xml_converter/src/trail_gen.hpp
+++ b/xml_converter/src/trail_gen.hpp
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <functional>
 #include <string>
 #include <vector>