John Colin McCormack (2 December 1941 – 19 June 2004) was a Welsh actor who enjoyed success in classical stage performances and television shows including BBC TV's Dixon of Dock Green, a show he returned to twenty years later when he played a police constable. McCormack also appeared in several feature films during his career.

McCormack was probably best known for his recurring role as Alan in the 1984 science fiction series Chocky and for playing Kevin Masters in EastEnders.

McCormack's electric presence and square jaw coupled with his imposing athletic build usually saw him typecast as a soldier or policeman. He nonetheless appeared in a wide range of roles including Man About the House, The Good Life and Yes, Minister. He also tutored and coached at the Guildhall School of Music and Drama where his students included Ewan McGregor, Daniel Craig and Damian Lewis.

McCormack died of cancer aged 62 after a short illness, following a tour of Romeo and Juliet in Hong Kong with the Royal Shakespeare Company.