Robert "Bob" Ostertag (born April 19, 1957) is a musician, writer, and political activist based in San Francisco. He has published seven books, one feature film, a DVD, twenty-six albums, and collaborated with numerous musicians. In his writing, films, and podcasts, he has addressed LGBT issues, poverty, climate change, and technology, from a militant yet non-ideological perspective. On March 25, 2006, Ostertag made all of his recordings to which he owns the rights available as digital downloads under a Creative Commons Attribution-NonCommercial 2.5 license.