Gary Edward Wagner (born June 28, 1940) is an American former professional baseball right-handed pitcher, who played in Major League Baseball (MLB) for the Philadelphia Phillies and Boston Red Sox from 1965 to 1970.

Listed as 6 feet 4 inches (1.93 m) tall and 185 pounds (84 kg), Wagner spent three years in the Philadelphia farm system before making the Phillies in 1965.

Wagner was primarily a relief pitcher during his MLB career, with only four starting assignments among his 162 total games pitched.

Boston picked him up in late May and assigned him to Triple-A, but released him again on July 5, ending his professional baseball career.

As a major leaguer, Wagner worked in 2671⁄3 innings pitched, allowing 250 hits and 126 bases on balls; he struck out 174 and was credited with 22 saves.