Harry Payne Whitney (April 29, 1872 – October 26, 1930) was an American businessman, thoroughbred horse breeder, and member of the prominent Whitney family.

Whitney was born in New York City on April 29, 1872, as the eldest son of Flora Payne and William C. Whitney (1841–1904), a very wealthy businessman and United States Secretary of the Navy. Whitney was the elder brother of William Payne Whitney (1876–1927). His sister Pauline Payne Whitney (1874–1916) married Almeric Hugh Paget, 1st Baron Queenborough (1861–1949), and his youngest sister Dorothy Payne Whitney (1887–1968) was married to Willard Dickerman Straight (1880–1918), and later to Leonard Knight Elmhirst (1893–1974) after Straight's death.

Whitney studied at Groton School in Groton, Massachusetts, then attended Yale University, graduating in 1894. He was a member of the Skull and Bones. After Yale, he spent two years at Columbia Law School, but he never finished his degree and decided to enter the world of sports and business. He was a member of the class of 1898. In 1904, after the death of his father, he inherited $24,000,000, and in 1917, he inherited approximately $12,000,000 along with the large steam yacht Aphrodite from his uncle, Oliver Hazard Payne.

An avid sportsman, Whitney was a ten-goal polo player. His love of the sport was inherited from his father, who had been involved with polo when it was first organized in the United States in 1876 by James Gordon Bennett, Jr. Whitney organized the U.S. polo team that beat England in 1909. "Whitney Field" polo field near Saratoga Springs, New York, is named for him.

He was a board member of the Montauk Yacht Club and competed with his yacht Vanitie in the America's Cup. Whitney also served on the board of directors of the Long Island Motor Parkway, built by his wife's cousin, William Kissam Vanderbilt II.

Whitney enjoyed quail hunting and purchased the 14,000-acre (57 km²) Foshalee Plantation in northern Leon County, Florida, from Sydney E. Hutchinson of Philadelphia, Pennsylvania.

Whitney was a major figure in Thoroughbred racing and in 2018 was voted one of the National Museum of Racing and Hall of Fame's most prestigious honors as one of the Pillars of the Turf.

Harry Whitney inherited a large stable from his father including the great filly Artful and her sire Hamburg, and in 1915 established a horse breeding farm in Lexington, Kentucky where he developed the American polo pony by breeding American Quarter Horse stallions with his thoroughbred mares. He was thoroughbred racing's leading owner of the year in the United States on eight occasions and the breeder of almost two hundred stakes race winners. His leading sire was first Hamburg and then the great sire Broomstick, by Ben Brush. His Kentucky-bred horse Whisk Broom II (sired by Broomstick) raced in England, then at age six came back to the U.S. where he won the New York Handicap Triple. He also owned Upset, who gave Man o' War the only loss of his career.