Robert Gilman Allen (July 10, 1867 – May 14, 1943) was an American shortstop for the Philadelphia Phillies, the Boston Beaneaters and the Cincinnati Reds, as well as a manager for two brief stints with the Phillies and Reds. He was born in Marion, Ohio, and as a youth, played baseball with future president Warren G. Harding. Allen made his NL debut in 1890 with the Phillies, and in his day was considered a power hitter, hitting a career high eight home runs in 1893. When Allen's contract was up, he took a three-year hiatus from baseball, but he later joined the Beaneaters. His playing time diminished and he walked away from baseball again after the 1897 season. In 1900, he was hired as manager of the Reds, occasionally inserting himself into the game as a shortstop. He finished 62–77 and in seventh place. He was fired after one season at the helm.