diff --git a/robots.txt b/robots.txt
index cf227989a71..534962cc3db 100644
--- a/robots.txt
+++ b/robots.txt
@@ -38,6 +38,9 @@ Disallow: /py-modindex.html
 Disallow: /search.html
 Disallow: /searchindex.js
 Disallow: /win32_*.tar.gz
+# exclude all of /devdocs except /devdocs/devel
+Disallow: /devdocs/
+Allow: /devdocs/devel/
 
 # tell robots this is sitemap
 Sitemap: https://matplotlib.org/_sitemap/sitemap.xml