Robert Gray Allen (October 23, 1937 – December 12, 2023) was an American Major League Baseball pitcher.

He had an impressive 1960 season with Cleveland's Mobile minor league affiliate with a 16–11 won-loss record.

Allen made his major league debut on April 14, 1961, with the Cleveland Indians at age 23.

After the season, the Indians traded Allen to the Pittsburgh Pirates on December 14 for players to be named.

After years of working back to the Major Leagues, Allen had a record of 2–2 and a 4.21 ERA in 1966, pitching 511⁄3 innings.