It shouldn't: name.github.io → example.com is a 301 redirect. However, https://github.com/name/name.github.io/blog/master/* https://github.com/name/name.github.

It shouldn't: name.github.io → example.com is a 301 redirect. However, https://github.com/name/name.github.io/blog/master/* https://github.com/name/name.github.io/blog/master/* and https://github.com/name/name.github.io/tree/master/* https://github.com/name/name.github.io/tree/master/* will show up in Google searches. Here's an example, using the atmos.org example the GitHub Pages documentation uses: https://www.google.com/search?q=Saying+how+it+was+%E2%80%9Csuper+light+and+fast+webserver+with+really+good(better+than+pound)+proxy+module.%E2%80%9D https://www.google.com/search?q=Saying+how+it+was+%E2%80%9Cs... One result for atmos.org, and then a duplicate result for https://github.com/atmos/atmos.github.io/blob/master https://github.com/atmos/atmos.github.io/blob/master. Here's a screenshot in case you see something different: http://i.imgur.com/TavoyuW.png http://i.imgur.com/TavoyuW.png The only way to prevent that from happening is to avoid using a branch named "master" in your repository.