Niksar (1962–1980) was a French-bred, British-trained Thoroughbred racehorse and sire, best known for winning the classic 2000 Guineas in 1965. After failing to win as a two-year-old he won his first race of 1965 by six lengths before winning the Guineas at Newmarket Racecourse. He failed to win in his remaining five starts and was retired at the end of the season with a record of two wins and two places from ten starts. He had moderate success as a breeding stallion in Australia and Japan.