Gregory John Kosc
- Height 6' 1", Weight 240 lb.
- School University of Texas at El Paso
Umpire Greg Kosc began his career in the Western Carolinas League in 1972. He moved to the Carolina League (1973), Southern League (1974), and Pacific Coast League (1975). Kosc moved to the American League in 1976.
His umpiring career ended in 1999 when he submitted his resignation as part of a failed negotiating ploy by the umpires union. In February of 2002, he was allowed to retire with back-pay and full benefits for the time missed. He was in a total of 3,255 games. He worked the 1981 and 1992 All-Star Games and the 1987 and 1997 World Series.