- 12 September 2006 – Release of documentary Dixie Chicks: Shut Up and Sing (conference pictured); tagline of film is "freedom of speech is fine as long as you don't do it in public"
- 22 September 1950 – U.S. President Harry Truman vetoed McCarran Internal Security Act, calling it "the greatest danger to freedom of speech, press, and assembly since the Alien and Sedition Laws of 1798", a "mockery of the Bill of Rights" and a "long step toward totalitarianism"
- 24 September 2011 – First add appeared in the Toronto, Canada National Post Ad Controversy
- 25 September 1789 – As part of the United States Bill of Rights, First Amendment to the United States Constitution submitted to the states for ratification