Vice Admiral John Charles O'Brien OC, CD (16 December 1918 – 24 March 1996) was a Canadian Forces officer who served as Commander Maritime Command from 19 July 1966 to 6 July 1970.

[1] He was in action off Norway in 1939, commanded a small boat at the Dunkirk evacuation in 1940, served as a Signals Officer for the Allied invasion of Sicily in 1943 during the Second World War.

[1] He went on to be Naval Member of the Canadian Joint Staff in Washington, D.C. in 1961, Senior Canadian Officer Afloat (Atlantic) in 1964 and Commander Maritime Command in 1966.

[1] His last appointment was as Commandant of the NATO Defense College in Rome in 1970 before retiring in 1973.

[1] O'Brien married Stephanie Frances Swire; she died on 2 October 2006.