Mark Edward Eaton (January 24, 1957 – May 28, 2021) was an American professional basketball player who spent his entire career (1982–1993) with the Utah Jazz of the National Basketball Association (NBA). Named an NBA All-Star in 1989, he was twice voted the NBA Defensive Player of the Year (1985, 1989) and was a five-time member of the NBA All-Defensive Team. Though limited offensively, the 7-foot-4-inch (2.24 m) Eaton became one of the best defensive centers in NBA history. He led the league in blocks four times and holds the NBA single-season records for blocks (456) and blocked shots per game average (5.6), as well as career blocked shots per game (3.5). His No. 53 was retired by the Jazz.

Eaton was a reserve on his high school basketball team before graduating and working as an auto mechanic. He was discovered by an assistant coach at Cypress College, who persuaded Eaton to enroll at the community college and play basketball. Eaton transferred to play college basketball for the UCLA Bruins, but he was used sparingly. He was drafted in the fourth round of the 1982 NBA draft by the Utah Jazz as a long-term project. Eaton helped transform the Jazz from a last-place team into a perennial playoff team. When he retired from playing in 1994, he ranked second in the NBA in career blocks behind Kareem Abdul-Jabbar.