John Gaston Peacock (January 10, 1910 – October 17, 1981) was a part-time catcher in Major League Baseball who played for three teams between 1937 and 1945.

A light-hitting catcher, Peacock was good defensively and knew how to handle his pitching staff.

Peacock entered the majors in 1937 with the Boston Red Sox, playing for them through the 1944 midseason before joining the Philadelphia Phillies (1944–1945) and Brooklyn Dodgers (1945).

A disciplinated hitter with a great knowledge of the strike zone, he posted a solid 2.51 walk-to-strikeout ratio (183-to-73).

In 518 appearances behind the plate, Peacock recorded 1863 outs, 220 assists, 37 double plays, and only 36 errors in 2119 total chances for a .983 fielding percentage.