Madalyn Murray O'Hair was an American activist supporting atheism, Holocaust denial, and separation of church and state. In 1963, she founded American Atheists and served as its president until 1986, after which her son Jon Garth Murray succeeded her. She created the first issues of American Atheist Magazine and identified as a "militant feminist".

American Atheists is a non-profit organization in the United States dedicated to defending the civil liberties of atheists and advocating complete separation of church and state. It provides speakers for colleges, universities, clubs, and the news media. It also publishes books and American Atheist Magazine.