Myer Prinstein (born Mejer Prinsztejn, December 22, 1878 – March 10, 1925) was a Poland-born American track and field athlete who held the world record for the long jump in 1900 and won four gold medals in three Olympic Games for the long jump and triple jump. He was a member of the Irish American Athletic Club in Queens, New York. A 1902 law graduate and track team captain for Syracuse University, after college he became a New York real estate lawyer and businessman while living in Jamaica Plains, Queens. To date, he is the only Olympic track athlete to win both the triple and long jump in the same Olympics, earning the distinction in St. Louis in 1904.

Prinstein was Jewish and was born in Szczuczyn, in Russian-ruled Congress Poland. His parents, Jacob and Julia Prinstein (born Jankiel Prinsztejn and Judes Rubinsztejn), emigrated to New York City. In 1883, when Myer was five, the family moved to Syracuse and resided at 724 Orange Street, currently McBride St., in the predominantly Jewish neighborhood of the 7th Ward, on the East side of downtown. Myer began competing in track and field while he attended the public Syracuse High School, which later became Central High, and he was a member of the local YMCA team. The family had five daughters and four sons; his father Jacob was a grocer and baker. Myer was the third oldest son and the fourth child.

Enrolling in 1897, Prinstein was captain of the Syracuse University track team, and graduated with a law degree in 1902. After graduating college, he moved to Jamaica, Queens, New York to practice law, where he was a member and competitor for the highly accomplished Irish American Athletic Club.

In 1908 he married Henrietta Northshield, who had been a New York City school teacher, and they had a son, Elsner, known as Eddie, born in June 1916.

In what was most likely his most significant athletic accomplishment outside of the Olympic games, while competing for Syracuse, Prinstein set a running long jump world record of 7.235 m (23 ft 8+7⁄8 in), increasing the prior record by several feet, in New York on June 11, 1898. However, the record was soon broken, first by William Newburn of Ireland on June 18, 1898, and then by future rival Alvin Kraenzlein on May 26, 1899.

Impressively, on April 28, 1900, Prinstein set a new world record of 7.50 m (24 ft 7+1⁄4 in) in Philadelphia, running at Philadelphia's well-attended Penn Relays. Four months later, on August 29, 1900, this record was also broken by Peter O'Connor of Ireland.

A versatile track and field athlete, besides specializing in the long and triple jumps, he ran sprints and relays, pole-vaulted, hurdled, and high-jumped during collegiate competition at Syracuse. He even played on one of the school's earliest basketball teams. He was lean but not exceedingly tall, and though his height estimates from various sources vary, Syracuse University publications place his height at 5 ft 7+3⁄4 in (172.1 cm).

Prinstein won the silver medal in the long jump at the 1900 Summer Olympics in Paris, France, losing to Alvin Kraenzlein after being denied permission by Syracuse officials to compete in the final because it was contested on a Sunday – despite the fact that Prinstein was a Jew, and Kraenzlein, who was a Christian, did compete. The two had had an informal agreement not to compete on Sunday: when Prinstein learned that Kraenzlein had competed, he became angry and, depending on the account, punched Kraenzlein in the face or was restrained from doing so. Sportsmanship was important to Prinstein, and despite their rivalry, he and Kraenzlein, a four-time gold medalist in 1904, became good friends and remained so throughout Prinstein's life. The following day, Prinstein won the gold medal in the hop, step and jump (triple jump), beating 1896 champion James Connolly with a leap of 14.47 meters which simultaneously set the Olympic Record.