diff --git a/static/robots.txt b/static/robots.txt
index 7dd3caf3e..04040f2c9 100644
--- a/static/robots.txt
+++ b/static/robots.txt
@@ -1 +1,7 @@
 Sitemap: https://docs.rs/sitemap.xml
+# Semver-based URL are always redirects, and sometimes
+# confuse Google's duplicate detection, so we block crawling them.
+# https://docs.rs/about/redirections
+User-Agent: *
+Disallow: */^
+Disallow: */~