The Raiders (10-17, 4-6), who snapped a three-game losing streak, led 38-16 with 4:04 left in the half.
Gabe Knutson and Anthony D'Orazio scored 17 points apiece and Holden Greiner had 12 for the Mountain Hawks (18-6, 8-2), whose four-game winning streak was halted. Lehigh was tied with Bucknell atop the Patriot League at 8-1, but Bucknell also lost, falling to Lafayette 63-62.
Colgate shot 38.1 percent on 3-pointers (8 of 21) to Lehigh's 16.7 percent (3 of 18), beat the Mountaineers on the boards 40-33, and the Raiders' bench outscored Lehigh's 15-2.
Lehigh tied Colgate at 56-all on a 3-pointer by D'Orazio with 3:04 left, but James Brandon made two free throws at 1:53, and Lehigh never caught up.