diff --git a/doc/en/reference/reference.rst b/doc/en/reference/reference.rst
index d8efbbbaa..7764b03eb 100644
--- a/doc/en/reference/reference.rst
+++ b/doc/en/reference/reference.rst
@@ -1,3 +1,5 @@
+:tocdepth: 3
+
 .. _`api-reference`:
 
 API Reference