John McGuffin (1942–2002) was an anarchist from Northern Ireland who was prominently involved with People's Democracy upon the onset of the Troubles in the 1970s.

[1] While still attending Queen's University, McGuffin became a prominent figure in People's Democracy, one of the main organisations involved in the Northern Ireland civil rights movement.

[2] Nonetheless, McGuffin denounced the Provisional IRA for Bloody Friday (1972) in which nine people were killed and 130 injured in a series of city centre bombings, writing "Twenty-two bombs in the heart of a crowded city in broad daylight are bound to kill people no matter what warnings are given, and the Provisional IRA must bear the full responsibilities for these murders.

From 1974 to 1981, McGuffin wrote for An Phoblacht under the pseudonym "the Brigadier", in a column which satirised the British army and its view of Northern Ireland.

[3] In the mid-1970s, McGuffin served as a part of an international committee which investigated the deaths in custody of members of the Red Army Faction in West Germany.