Surplice (1845–1871) was a British Thoroughbred racehorse and sire. In a career that lasted from July 1847 to October 1849 he ran thirteen times and won nine races. He was the leading colt of his generation in England at both two and three years old, with his wins including The Derby and the St Leger in 1848: he was the first horse for forty-eight years to win both of these Classics. His later career was less successful and he was retired to stud in 1850. Surplice had limited success as a sire of winners and died in 1871.

Surplice was a dark bay horse with a small white star standing 16.1 hands high, making him an unusually large Thoroughbred for his time. He was bred by Lord George Bentinck, the dominant figure in British horse-racing of his era. In 1846, Bentinck decided to concentrate on his political affairs and sold all his racing interests, including the yearling Surplice, to Edward Lloyd-Mostyn for £10,000. A condition of the deal was that Surplice should remain with his trainer John Kent at Goodwood. Later that year Mostyn sold Surplice to Lord Clifden.

Surplice's sire, Touchstone, won the St Leger and two Ascot Gold Cups, before going on to be an outstandingly successful stallion. Apart from Surplice, his classic winners included Cotherstone, Orlando and Newminster and he was Champion sire on four occasions. Surplice's dam, Crucifix, was an undefeated racemare who won the 1000 Guineas, 2000 Guineas and Epsom Oaks in 1840.

Surplice began his racing career in July 1847 at Goodwood when he ran in the Ham Stakes. He was made the 4/7 favourite and the result was never in doubt as he led from the start and won easily by two lengths from Liston. Immediately after the race the bookmakers offered odds of only 10/1 against him for the following year's Epsom Derby. He followed up in the Produce Stakes at the same meeting, starting at odds of 1/3 and winning by three lengths in a race which was described as "all one way".

In September he was sent to Doncaster, where he won the Municipal Stakes. At Newmarket in October, he was allowed a walkover in the Buckenham Stakes, when no horse appeared to oppose him. His earnings of £5,550 were the highest for any British two-year-old that season and his performances were sufficient to send him into the winter break regarded as the leading contender for the following year's Derby.

Surplice maintained his position as Derby favourite in early 1848, despite a series of negative rumours which seemed to originate from Lord Clifden's racing manager, Francis Villiers who had a strong financial interest in his stable companion, Loadstone.

Surplice made his first appearance of the season in the Derby at Epsom. He started the even-money favourite in a field of seventeen runners. Ridden by Sim Templeman, he was settled in fifth place before moving up to turn into the straight in third place. Two furlongs from the finish Templeman sent Surplice into the lead, where he looked to be going well, but was soon challenged by Shylock. Surplice successfully turned back the challenge but had to be ridden hard to hold the late run of Springy Jack and win by a neck. After the race Benjamin Disraeli was attempting to console Lord George Bentinck who was downhearted at having sold the horse who had won the Derby. When Bentinck told Disraeli that a man not involved in racing could not possibly understand the significance of the race Disraeli replied that he knew perfectly well that the Derby was "the Blue Ribbon of the Turf".

At Goodwood in July, Surplice ran twice but appeared to be completely unsuited by the soft ground and was beaten in both his races. On the Tuesday of the meeting he finished second to Distaffina in the Gratwicke Stakes over one and a half miles and two days later he finished third to Glendower in the one mile Racing Stakes. Surplice had been odds-on favourite for both races. He was then transferred to the stable of Robert Stephenson.