Delaware (5-8, 0-2) led briefly before Kent and Grays combined for six of the eight 3-pointers James Madison scored in building a 35-20 halftime lead.
The Dukes pulled ahead in the second half and led by 18, 43-25, on Ron Curry's 3-pointer with 16:28 left. Delaware finished with a 9-0 row in which Devon Pinkard hit a 3 with 54 seconds to go.
Anthony Mosely scored 16 points and grabbed a career-high 11 rebounds for Delaware, which has lost six of its last eight matchups to James Madison. Cazmon Hayes added 17 points.