Ivan Leigh Head OC QC (July 28, 1930 – November 1, 2004) was a Canadian lawyer, legal scholar, and civil servant. He was an influential foreign policy adviser of Prime Minister Pierre Trudeau. Born in Calgary, Alberta, he received a Bachelor of Arts degree in 1951 and a Bachelor of Laws degree in 1952 from the University of Alberta. He was called to the Bar of Alberta in 1953 and was created a Queen's Counsel in 1974. He practiced law in Calgary from 1953 to 1959. He was then awarded Harvard University's Frank Knox Memorial Fellowship and received a Master of Laws degree from Harvard Law School in 1960.