Marcus Smart scored 14 for the Cowboys (20-6, 10-4 Big 12), who rebounded from Wednesday's double-overtime loss to Kansas.
Brian Williams came off the bench to contribute 13 points and six rebounds for Oklahoma State.
The Mountaineers (13-14, 6-8) got 11 points from Aric Murray and 10 from Matt Humphrey.
Penelope Cruz named 2013's 'Best Body' by Fitness magazine
Susan Sarandon: I was stoned at almost every awards show