diff --git a/doc/conf.py b/doc/conf.py
index b6672c71..628fc172 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -113,20 +113,21 @@ smartquotes = False
 
 # -- Options for HTML output -------------------------------------------------
 
+# Theme options are theme-specific and customize the look and feel of a theme
+# further.  For a list of options available for each theme, see the
+# documentation.
+#
+html_theme_options = {}
+
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
 #
 if on_rtd or os.environ.get('USE_RTD_THEME', '0') == '1':
   html_theme = 'sphinx_rtd_theme'
+  html_theme_options['collapse_navigation'] = False
 else:
   html_theme = 'alabaster'
 
-# Theme options are theme-specific and customize the look and feel of a theme
-# further.  For a list of options available for each theme, see the
-# documentation.
-#
-# html_theme_options = {}
-
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".