Harold Andrew Allen (born July 23, 1940 in Wampum, Pennsylvania) is a former outfielder in Major League Baseball who played for the Washington Senators (1966-1970), Milwaukee Brewers (1970) and Chicago White Sox (1972-1973). He is the brother of Dick Allen and Ron Allen.
In his major league career, Allen also played third base, second base, and first base, and even made one appearance as a catcher. As an outfielder he was just fair defensively, making 16 errors in 374 total chances for a .957 fielding percentage. His most productive season came in 1969 for the Senators, when he posted career-highs in batting average (.277), runs (42), hits (75) and RBI (17).
- hit a home run in his sixth major league at-bat off Tommy John (September 23, 1966)
- hit a game-tying pinch-hit home run in the top of the eighth inning against the Chicago White Sox (April 16, 1967)
- a pair of 4-hit games – four singles against the White Sox (September 25, 1966) and a double, triple and two singles against the Detroit Tigers (July 24, 1968)
- twelve 3-hit games, the most impressive being two singles and a triple against the Minnesota Twins (August 13, 1968)
- hit a combined .319 (22-for-69) against All-Stars Mike Cuellar, Mickey Lolich, and Sam McDowell
- As of September, 2006, the Allen brothers ranks 11th in the MLB brother-combination, home run list with 358 dingers (out of more than 350 combinations all-time)
- Allen led the Pioneer League in RBI (140) and batting average (.346), and tied for the league lead in hits (176) and home runs (37) while playing for the Magic Valley Cowboys in 1962.
- He led the Pacific Coast League with 288 total bases while playing for the Hawaii Islanders in 1966.
- 1971 Baseball Register published by The Sporting News