Javan Felix added 17 points and Cameron Ridley supplied 16 points with 11 rebounds as the Longhorns (14-4, 3-2 Big 12) won a third straight.
The Cyclones (14-3, 2-3) got 18 points, six assists and five rebounds from Georges Niang but continued to stumble after getting off to the best start in school history.
It was Iowa State's 11th loss in 12 visits to Texas.
Melvin Ejim provided a double-double of 17 points and 10 rebounds.
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