Mark Tremell McLemore (born October 4, 1964) is a former second baseman and utility player in Major League Baseball.

He played for the California Angels 1986-1990, Cleveland Indians 1990, Houston Astros 1991, Baltimore Orioles 1992-1994, Texas Rangers 1995-1999, Seattle Mariners 2000-2003, and Oakland Athletics 2004.

McLemore's primary claim to fame is his nickname "Supersub", which he earned due to his contributions to the 2001-03 Seattle Mariners. The club's regular 2nd baseman during the 2000 season, in 2001 McLemore was replaced by Bret Boone, acquired during the offseason. With McLemore openly bitter about losing his job, Manager Lou Piniella appeased him by using him regularly in a variety of infielder and outfielder positions (mainly LF, 3B and SS, but also 2B, CF, DH and RF), with remarkable results. During the 2001 Mariners' record-tying 116-win season, he racked up 409 at-bats, 117 hits, 69 walks, .286 batting average, .384 OBP and 39 stolen bases—all while playing without a regular position.

McLemore's statistics dropped steadily from his 2001 peak until he left the Mariners after 2003 as a free agent. He retired after one season with Oakland (2004). By having played with Oakland in his final year, McLemore became the first major leaguer to have played for all four teams in the American League West since MLB divisions were realigned in 1994 (Gene Nelson also played for all four AL West teams, but his career ended in 1993, prior to the realignment). He is also one of a handful of players to play for both the Rangers and the Astros, Texas' two MLB franchises.

McLemore had a brief stint as a color commentator for baseball games on ESPN, and currently serves as part of the Texas Rangers broadcast team, he provides analysis on the pre and post game programs on Fox Sports Southwest. He also does analysis on the Friday night Texas Ranger broadcasts on TXA21 (KTXA) with Gina Miller.