Macdonald "Mac" Benson (born June 30, 1930 in Wilmington, Delaware) is a Canadian Horse Racing Hall of Fame trainer. A resident of Woodbridge, Ontario, Benson came to Canada in 1978 to train for E. P. Taylor's renowned Windfields Farm. Since then, horses trained by Benson have won ten Sovereign Awards and four Canadian Classics.Mac Benson embarked on his professional training career in 1958 and began by working for prominent Delaware Thoroughbred owner, William du Pont, Jr.