diff --git a/doc/source/development.rst b/doc/source/development.rst
index 7a47c267d..85b050b03 100644
--- a/doc/source/development.rst
+++ b/doc/source/development.rst
@@ -142,6 +142,7 @@ correctly. `Sphinx <http://sphinx-doc.org/>`_ is used to generate the documentat
 
     cd doc
     pip install -r requirements-doc.txt
+    pip install -U -r requirements-rtd.txt # important for reproducing the deployment environment
     make html
 
 Once done, the docs will be in ``doc/_build/html``. For example, on Mac