diff --git a/docs/conf.py b/docs/conf.py
index c3f0ca37c1..dc186985bc 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -32,7 +32,7 @@
 # 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','sphinx.ext.intersphinx','sphinx_design',]
+extensions = ['sphinx.ext.autodoc','sphinx.ext.intersphinx','sphinx_design','sphinx_rtd_theme',]
 
 # settings for ReadTheDocs PDF creation
 latex_engine = 'pdflatex'
diff --git a/docs/requirements.txt b/docs/requirements.txt
index 0b266552df..5debf98be5 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,3 +1,4 @@
 sphinx-gallery
 sphinxcontrib-bibtex
 sphinx-design==0.3.0
+sphinx_rtd_theme==1.3.0