diff --git a/lib/db_ido/dbtype.h b/lib/db_ido/dbtype.h
index 3d4c206f6..3dde29557 100644
--- a/lib/db_ido/dbtype.h
+++ b/lib/db_ido/dbtype.h
@@ -24,6 +24,7 @@
 #include "base/object.h"
 #include "base/registry.h"
 #include "base/singleton.h"
+#include <set>
 
 namespace icinga
 {