Sir Ivor was an American-bred, Irish-trained champion Thoroughbred racehorse and sire. In a career which lasted from July 1967 to October 1968 he ran thirteen times and won eight races. He won major races in four countries: the National Stakes in Ireland, the Grand Criterium in France, the 2000 Guineas, Epsom Derby and Champion Stakes in England and the Washington, D.C. International in the United States.

The 2000 Guineas Stakes is a Group 1 flat race in Great Britain open to three-year-old thoroughbred colts and fillies. It is run on the Rowley Mile at Newmarket over a distance of 1 mile (1.6 km) and scheduled to take place each year at the start of May.