diff --git a/doc/source/conf.py b/doc/source/conf.py
index 180e84fa323..01abfbbebd4 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -46,7 +46,7 @@ sys.path.insert(1, os.path.abspath(os.path.join(os.path.dirname(__file__), os.pa
 
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
-extensions = ['sphinx.ext.autodoc']
+extensions = ['sphinx.ext.autodoc', 'sphinx.ext.intersphinx']
 if not SKIP_SOURCE:
     extensions += ['sphinx.ext.doctest', 'sphinx.ext.todo', 'sphinx.ext.coverage', 'sphinx.ext.viewcode']
 
@@ -132,6 +132,8 @@ pygments_style = 'sphinx'
 # A list of ignored prefixes for module index sorting.
 #modindex_common_prefix = []
 
+# Intersphinx mapping to Python 2.7 documentation
+intersphinx_mapping = {'python': ('https://docs.python.org/2.7', None)}
 
 # -- Options for HTML output ---------------------------------------------------