- American Civil Liberties Union
- American Civil Liberties Union of Ohio
- American Civil Liberties Union of Utah
- Americans United for Separation of Church and State (1994)
- Americans United for Separation of Church and State (2006)
- Americans for Religious Liberty
- Council of Europe
- Freedom from Religion Foundation
- Institute for First Amendment Studies
- National Committee for Public Education and Religious Liberty
- People for the American Way Foundation