Gary Charles Peters (born April 21, 1937 in Grove City, Pennsylvania) is a former pitcher in Major League Baseball. The Chicago White Sox drafted Peters as an amateur free agent in 1956 after he graduated from Grove City College. He joined the major league club for keeps in 1963 and proceeded to win Rookie of the Year honors that year. He stayed in the White Sox organization until 1969, when he was traded to the Boston Red Sox for the last three years of his career. He was selected to the All-Star Game in 1964 and 1967, and finished in the top 10 in the Most Valuable Player voting in 1963, 1964 and 1967.
Peters led the American League pitchers in earned run average twice while with the White Sox, with a teammate finishing runner-up both years. In his rookie season of 1963 his 2.33 ERA edged out Juan Pizarro's 2.39; in 1966 his 1.98 ERA was nearly a half-run ahead of Joe Horlen's 2.43. The latter led the league in earned run average in 1967 at 2.06; Peters was second at 2.28.
Peters was also one of the best hitting pitchers of his era, with 19 career home runs, and a .222 career batting average. He was used occasionally as a pinch hitter, even winning a game with a pinch hit home run on one occasion. On May 5, 1968, Peters hit a grand slam in Comiskey Park, helping the White Sox to a 5-1 victory over the New York Yankees.