INDIANAPOLIS (AP) Denzel Valentine
The league's player of the year sealed it with two free throws with 0.8 seconds to go, and Melo Trimble's desperation heave from 55 feet away didn't get past midcourt.
Michigan State (28-5) has won 12 of 13 and will face No. 13 Purdue in Sunday's title game.
Robert Carter Jr. had 18 points and eight rebounds to lead Maryland. Trimble finished with 11 points.
Despite making only two baskets over the final 10 1/2 minutes, the Terrapins still could have taken the lead after Valentine missed the front end of a one-and-one.