William & Mary (17-10, 11-5 Colonial Athletic Association) is in a four-way tie for first place in the CAA. Hofstra (18-11, 9-7) remains in fifth place, two games back of the leaders.
Thornton scored back-to-back layups to give the Tribe a 77-71 lead with 1:57 left. Ameen Tanksley hit a 3 and Juan'ya Green made two throws to pull Hofstra within 77-76. Thornton split a pair a free throws and Green hit a jumper to tie it before Thornton made both free throws to win the game.
Green scored 21 points to lead five in double figures for Hofstra.