Golden Fleece (1 April 1979– 18 March 1984) was an American-bred, Irish-trained champion Thoroughbred race horse. In a career which consisted of only four races, he was undefeated, with his most notable success coming on his final racecourse appearance in the 1982 Epsom Derby. In that race he recorded the fastest winning time since before WWII. Sent to stud, the horse contracted stomach cancer and died in March 1984 after only one year's stud duty.

Golden Fleece was a big, heavily built bay horse bred in the United States by Mr and Mrs Paul Hexter. He was foaled and raised at Hilary J. Boone's Wimbledon Farm in Fayette County, Kentucky. As a yearling, the horse was bought for $775,000 by Robert Sangster. He was sent to Ireland to be trained by Vincent O'Brien at Ballydoyle.

Golden Fleece was sired by Nijinsky, the Canadian-bred winner of the English Triple Crown in 1970 who went on to become a very important stallion. Golden Fleece's dam, Exotic Treat, was a half-sister to What A Treat, the dam of leading miler and champion sire, Be My Guest.

Golden Fleece's first race was in September 1981 when he contested a one-mile maiden race at Leopardstown. Ridden by Pat Eddery, he took the lead in the straight and won decisively from Assert. Golden Fleece did not race again in 1981, but his form was boosted when Assert won the Beresford Stakes by four lengths.

In the spring of 1982, Golden Fleece established himself as a leading contender for the Derby by winning the Ballymoss Stakes, beating older horses including the future Royal Ascot Prince of Wales's Stakes and Japan Cup winner Stanerra, at the Curragh. In the Nijinsky Stakes at Leopardstown, he again beat Assert. This form proved very strong when Assert subsequently won the French Derby, Irish Derby and the Benson and Hedges Gold Cup. Golden Fleece's participation in the Derby was briefly put in doubt by a minor training injury, but he made a quick recovery.

In the Derby, Golden Fleece started 3/1 favourite in a field of eighteen runners. His task was made slightly easier by the late withdrawal of his main rival in the betting, the Henry Cecil-trained Simply Great. Ridden by Eddery, Golden Fleece was held towards the back of the field on the turn into the straight. He was then switched to the outside, made rapid progress, took the lead a furlong out and won by three lengths. Again, the form would be franked, as the runner-up Touching Wood won the St Leger and Irish St. Leger. The Derby third, Silver Hawk, also produced good form.

Golden Fleece's winning time of 2:34.27 was the fastest for almost fifty years. After the race, Eddery called the winner "the best horse I have ever sat on".

Golden Fleece had training problems after his win at Epsom and was retired to stud without racing again.