diff --git a/doc/source/conf.py b/doc/source/conf.py
index be2efea28d..4937bd5889 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -43,6 +43,7 @@
     "sphinx.ext.napoleon",
     "sphinx.ext.intersphinx",
     "sphinx_copybutton",
+    "sphinx.ext.viewcode",
     "recommonmark",
     "nbsphinx",
 ]