Martin Robert Foster
- Height 5' 11", Weight 210 lb.
- High School Thomas Jefferson High School (Denver)
Marty Foster was an MLB umpire from 1996 to 2022. He began in the Appalachian League in 1988 and then moved up to the Midwest League (1989), Southern League (1991-1993), International League (1994), Pacific Coast League (1995-1996), American Association (1997) and IL again (1998-1999). He came to the majors in 1996 as part of the American League staff but did not get a full-time job until the two leagues merged their umpiring crews in 2000. He worked the 2002 All-Star Game.
Foster made a controversial call early in the 2013 season, with the Texas Rangers' Joe Nathan looking for his 300th career save with a 5-4 lead over the Tampa Bay Rays. With two outs, a runner on third and a full count on Ben Zobrist, Nathan threw a change-up that appeared to be well outside and almost in the dirt; Zobrist tossed his bat away and began to walk towards first base when Foster made a belated strike call, ending the game. Nathan was as surprised as Rays manager Joe Maddon, who came out to argue the call to no avail. After the game, Foster admitted that he had blown the call.
He retired following the 2022 season after 27 years and over 2,700 games. He was one of ten senior umpires to retire following that season.
His father-in-law George Spelius was a long-time minor league executive and was president of the MWL while Foster worked there.