diff --git a/doc/conf.py b/doc/conf.py
index fb1799a..41c1cfe 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -110,8 +110,16 @@
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
-import sphinx_rtd_theme
-html_theme = 'sphinx_rtd_theme'
+#
+# Code below copied from:
+# http://docs.readthedocs.org/en/latest/theme.html#how-do-i-use-this-locally-and-on-read-the-docs
+# on_rtd is whether we are on readthedocs.org
+on_rtd = os.environ.get('READTHEDOCS', None) == 'True'
+
+if not on_rtd:  # only import and set the theme if we're building docs locally
+    import sphinx_rtd_theme
+    html_theme = 'sphinx_rtd_theme'
+    html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 
 # 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
@@ -119,7 +127,10 @@
 #html_theme_options = {}
 
 # Add any paths that contain custom themes here, relative to this directory.
-html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
+# Note: the RTD theme path is commented out because it is added above
+# **only** when not building on RTD itself. See:
+# http://docs.readthedocs.org/en/latest/theme.html#how-do-i-use-this-locally-and-on-read-the-docs
+# html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 
 # The name for this set of Sphinx documents.  If None, it defaults to
 # "<project> v<release> documentation".