Equipoise (1928–1938) was a champion thoroughbred racehorse, a chestnut bred in the United States by Harry Payne Whitney and owned by his son, Cornelius Vanderbilt Whitney. He was called the Chocolate Soldier by his fans, due to his elegance and symmetry—living up to his name.
Equipoise raced against very strong opponents in 1930 and 1931 when he was part of what the Chicago Tribune newspaper called the "big four" in racing which included Jamestown, Mate, and Twenty Grand.  As a two-year-old, Equipoise got his first stakes victory when he won the Keene Memorial Stakes at Belmont Park. He then beat Twenty Grand and Mate to win the Pimlico Futurity, despite being left in the gate and racing right out of two of his shoes. When his jockey Sonny Workman was asked if this was his greatest race, Workman replied: "My greatest race? Hell, it may have been the greatest race anybody ever saw."
A hoof crack cut his two-year-old season short, and as a three-year-old he raced only three times.
At 4, however, he won the Metropolitan Handicap, the Stars and Stripes Handicap, and Whitney Stakes...and set a world record of 1:34⅖ for the mile at Arlington Park. At 5, Equipoise gave 26 pounds to the runner-up in again winning the Metropolitan. He also won the Suburban Handicap carrying 132 pounds. At 6 he won the Philadelphia and Dixie Handicaps, and the Whitney Gold Trophy.
Of his 51 Starts, he won 29, placed ten times, and had 4 shows. His career earnings were $338,610.
In the Blood-Horse magazine ranking of the top 100 U.S. thoroughbred champions of the 20th Century, Equipoise was ranked #21. Equipoise was also inducted into the National Museum of Racing and Hall of Fame in Saratoga Springs, New York in 1957.
In "Fugue for Tinhorns," the opening number of the musical Guys and Dolls, Equipoise is referred to as the great-grandfather of one of the song's fictional racehorses.