Allen hit 351 home runs and is one of just 26 players in baseball history to win both a Rookie of the Year and MVP awards.
He played in Philadelphia for nine seasons over the course of his career.
Phillies fans say his induction into the Hall of Fame in Cooperstown, New York, was long overdue.
The Phillies retired Allen's #15 jersey during a special celebration at Citizens Bank Park back in 2020 before he died.
Former Phillie Billy Wagner was also part of this year's Hall of Fame class.
The left-handed closer played two seasons with the Phillies.
Wagner posted his best career ERA and led the league in games finished during the 2005 season with the Phillies.
His 422 saves are more than all but one left-handed pitcher in the history of baseball.