diff --git a/docs/Makefile b/docs/Makefile
index 9c171972f..afe53b472 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -2,7 +2,7 @@
 #
 
 # You can set these variables from the command line.
-SPHINXOPTS    =
+SPHINXOPTS    = -W
 SPHINXBUILD   = sphinx-build
 SPHINXPROJ    = dask-ml
 SOURCEDIR     = source