diff --git a/python/templates/DatamodelDefinition.h.jinja2 b/python/templates/DatamodelDefinition.h.jinja2
index ce4cefb41..30264871e 100644
--- a/python/templates/DatamodelDefinition.h.jinja2
+++ b/python/templates/DatamodelDefinition.h.jinja2
@@ -1,5 +1,8 @@
 // AUTOMATICALLY GENERATED FILE - DO NOT EDIT
 
+#ifndef {{ package_name.upper() }}_DATAMODELDEFINITION_H
+#define {{ package_name.upper() }}_DATAMODELDEFINITION_H
+
 #include "podio/DatamodelRegistry.h"
 #include "podio/SchemaEvolution.h"
 
@@ -64,3 +67,5 @@ namespace static_registration {
 }
 
 } // namespace {{ package_name }}::meta
+
+#endif
\ No newline at end of file