Tyler Lanier Walker (born May 15, 1976) is an American former professional baseball relief pitcher.

Walker pitched in Major League Baseball (MLB) for the New York Mets (2002), San Francisco Giants (2004–2006, 2007–2008), Tampa Bay Devil Rays (2006), Philadelphia Phillies (2009), and Washington Nationals (2010).

On June 17, in a game against the Detroit Tigers, Walker made history by becoming the first pitcher to record a save (since the save rule became an official stat in 1969) by entering a game with the bases loaded with nobody out and proceeding to strike out all three batters he faced without allowing a run to score.

Early in the 2006 season, Walker was sent to the Tampa Bay Devil Rays in exchange for minor leaguer Carlos Hines.

On June 14 of that year, he was placed on the disabled list with a strained right elbow, and later underwent season-ending Tommy John surgery.