diff --git a/doc/conf.py b/doc/conf.py
index 32713d3084a7..3e9ccedd42e8 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -161,6 +161,7 @@
 
 # If false, no module index is generated.
 #html_use_modindex = True
+html_domain_indices = ["py-modindex"]
 
 # If true, the reST sources are included in the HTML build as _sources/<name>.
 #html_copy_source = True