Sweet Idea (September 22, 2010 –) is a Thoroughbred racehorse who was bred in Australia. On retirement in April 2015, Sweet Idea was the richest mare her age (or younger) in the world. She is the most successful horse in Magic Millions of all time, having placed second in the two-year-old Gold Coast Magic Millions (2012) and going on to win the three-year-old Gold Coast Magic Millions (2013) – no horse has ever won both races. She was the winner of the Group 1 Canadian Club Galaxy and a multiple Group race winner.