Coach Mark Turgeon says Trimble made the decision after considering a possible jump to the NBA.
Turgeon said Wednesday that Trimble discussed his options with the coach and family members before deciding that returning to Maryland was the best choice.
Trimble says he wants to build on what he and his teammates accomplished this season.
With Trimble playing a key role, Maryland finished second in the Big Ten and won a game in the NCAA Tournament before being eliminated by West Virginia.
Trimble ran the offense and led the Terrapins in scoring, averaging 16.2 points per game. He made 207 free throws, third-most in Maryland history for a season.