diff --git a/docs/source/contents.rst b/docs/source/contents.rst
index e2fbdf0f..2def4b8a 100644
--- a/docs/source/contents.rst
+++ b/docs/source/contents.rst
@@ -4,10 +4,7 @@
 Table of contents
 =================
 
-.. toctree::
-    :hidden:
-
-    index
+.. Keep this toctree in sync with the one at the bottom of index.rst.
 
 .. toctree::
     :maxdepth: 2
diff --git a/docs/source/index.rst b/docs/source/index.rst
index dfc1a2ad..9e024348 100644
--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -61,3 +61,17 @@ Miscellaneous
 
 - :doc:`releases/index`
 - :doc:`internals`
+
+.. Keep this toctree in sync with contents.rst.
+
+.. toctree::
+    :hidden:
+    :maxdepth: 2
+
+    intro/index
+    topics/index
+    ref/index
+    howto/index
+    faq
+    releases/index
+    internals