diff --git a/.github/workflows/deploy-website.yml b/.github/workflows/deploy-website.yml
index e231e510..4de5cfcf 100644
--- a/.github/workflows/deploy-website.yml
+++ b/.github/workflows/deploy-website.yml
@@ -63,7 +63,8 @@ jobs:
         run: bundle exec jekyll build
       - name: Validate HTML output
         working-directory: ./website
-        run: bundle exec htmlproofer --no-check-external-hash --swap-url 'https\://error-prone.picnic.tech:' ./_site
+        # XXX: StackOverflow returns a 403 when run on GHA.
+        run: bundle exec htmlproofer --no-check-external-hash --swap-url 'https\://error-prone.picnic.tech:' --ignore-urls '/^https:\/\/stackoverflow.com\/.*/' ./_site
       - name: Upload website as artifact
         uses: actions/upload-pages-artifact@56afc609e74202658d3ffba0e8f6dda462b719fa # v3.0.1
         with: