diff --git a/rtd-requirements.txt b/rtd-requirements.txt
new file mode 100644
index 0000000..443bdca
--- /dev/null
+++ b/rtd-requirements.txt
@@ -0,0 +1,5 @@
+# This file is strictly for building docs on readthedocs.org
+# See pyproject.toml for local development
+Sphinx==1.7.9
+sphinx-rtd-theme==0.4.3
+sphinxcontrib-contentui==0.2.2