diff --git a/indexer/categories_index.hpp b/indexer/categories_index.hpp
index 5a9b860dc4..a95f1dc2c3 100644
--- a/indexer/categories_index.hpp
+++ b/indexer/categories_index.hpp
@@ -1,3 +1,5 @@
+#pragma once
+
 #include "categories_holder.hpp"
 
 #include "base/mem_trie.hpp"