Air Marshal William Ross MacBrien, OBE, CD, RCAF (1913–1986), commonly known as Bill MacBrien or Iron Bill, was a senior Royal Canadian Air Force officer during World War II and a senior commander in the 1950s and 60s.

He joined the Royal Canadian Air Force in 1935 and during World War II he commanded a Canadian fighter sector in continental Europe.

In the early 1950s, he was a senior staff officer at the Headquarters of Canada's Air Defence Command in Saint-Hubert, Quebec before being appointed to further staff duties at No.

[3] Deputy commander in chief at the SHAPE HQ in Belgium in 1967.

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