Whistlejacket is an oil-on-canvas painting from about 1762 by the British artist George Stubbs showing the Marquess of Rockingham's racehorse approximately at life-size, rearing up against a plain background. The canvas is large, lacking any other content except some discreet shadows, and Stubbs has paid precise attention to the details of the horse's appearance. It has been described as "a paradigm of the flawless beauty of an Arabian thoroughbred". Through his dam, his bloodlines trace back to the "royal mares" imported by King Charles II, and his sire, Mogul, was a son of the Godolphin Arabian. The Godolphin Arabian was one of the three foundation sires of the Thoroughbred breed (along with the Darley Arabian and Byerly Turk). The Fitzwilliam family, heirs of the childless Rockingham, retained the painting until 1997 when funding from the UK Heritage Lottery Fund allowed the National Gallery, London to acquire it for £11 million.

Whistlejacket is an oil-on-canvas painting from about 1762 by the British artist George Stubbs showing the Marquess of Rockingham's racehorse approximately at life-size, rearing up against a plain background. The canvas is large, lacking any other content except some discreet shadows, and Stubbs has paid precise attention to the details of the horse's appearance. It has been described as "a paradigm of the flawless beauty of an Arabian thoroughbred". Through his dam, his bloodlines trace back to the "royal mares" imported by King Charles II, and his sire, Mogul, was a son of the Godolphin Arabian. The Godolphin Arabian was one of the three foundation sires of the Thoroughbred breed (along with the Darley Arabian and Byerly Turk). The Fitzwilliam family, heirs of the childless Rockingham, retained the painting until 1997 when funding from the UK Heritage Lottery Fund allowed the National Gallery, London to acquire it for £11 million.