Harbinger (foaled 12 March 2006) is a retired thoroughbred racehorse best known for winning the King George VI and Queen Elizabeth Stakes in 2010.

He was sold at yearling auction for 180,000 guineas and entered into the ownership of the Admiral Rous group, one of several syndicates operated by Highclere Throroughbred Racing.

Those performances saw him start second favourite in the King George behind his stable companion Workforce, the winner of the 2010 Epsom Derby.

However, Harbinger proved to be far too good in the King George, winning by 11 lengths over a field which also included Irish Derby winner Cape Blanco, triple Prix de l'Arc de Triomphe runner-up Youmzain and Hong Kong Vase winner Daryakana.

[7] In the autumn of 2017 he had his first Grade 1 winners when his three-year-old daughters Deirdre and Mozu Katchan won the Shuka Sho and the Queen Elizabeth II Cup respectively before the colt Persian Knight took the Mile Championship.