Richard Keith Mahler (/ˈmeɪ.lɜːr/; August 5, 1953 – March 2, 2005) was a starting pitcher in Major League Baseball who played for the Atlanta Braves (1979–1988, 1991), Cincinnati Reds (1989–1990) and Montreal Expos (1991).

Mahler started on opening day for the Braves in 1982, when Atlanta won the National League West title.

Mahler was a key member of the 1990 Reds' pitching staff as a spot starter and reliever, going 7–6 and contributing four saves.

After retiring, Mahler served as a minor league pitching coach for the Kansas City Royals and the Florida Marlins, and he was a roving instructor for the St. Louis Cardinals.

Mahler died at age 51 of a heart attack at home in Jupiter, Florida, where he was preparing for his second season as a minor league pitching coach for the New York Mets.