Texas (22-2, 11-2 Big 12) led 49-45 going into the fourth quarter. But OU (17-7, 8-5 B12) outscored Texas 29-7 in the 4Q.
Texas All-American candidate Imani Boyette was hounded inside and finished just 2-of-12 shooting for the game.
The Longhorns opened the fourth quarter 0-for-8 shooting, including four missed layups, and finished the 4Q 2-of-13 on FGs (6 missed layups) and 3-of-8 FTs.
"We just didn't look like we had the competitive spirit," Texas coach Karen Aston said. "I thought we fought hard. But we weren't nearly as competitive as they were. They were just the better team today."
Brooke McCarty was the only Longhorn in double figures in scoring with 19 points (6-15 FG, 3-7 3PT).
NEXT UP: ... home game Wednesday at 7 pm CT vs Kansas State (16-8, 6-7 Big 12)