The Rams (19-3, 7-2 Atlantic 10 Conference) led 69-45 with 9:55 left, then withstood a late comeback by the Minutemen (8-15, 2-7).
Anthony Gurley scored all 15 of his points in the final 3:15 for Massachusetts, and his fourth 3-pointer cut Rhode Island's lead to 91-85 with 16 seconds left.
Massachusetts quickly fouled Delroy James, whose two free throws gave the Rams their final margin.
Ricky Harris scored a season-high 32 points to move into fourth place on Massachusetts' career scoring list. He has 1,760 points and moved ahead of Lorenzo Sutton (1,731) and Rashaun Freeman (1,744).
Will Martell added 13 points for Rhode Island, including seven in a row that gave the Rams a 37-22 lead in the first half, when they forced 17 of Massachusetts' 21 turnovers.