Oklahoma State opened the game on an 11-4 run and produced 10 consecutive points later in the first half to take control.
The Cowboys made 8-of-16 from 3-point range, seven of those successful shots coming in the first half. Markel Brown chipped in 14 points and LeBryan Nash had 13.
Oklahoma State (15-2, 3-1 Big 12 Conference) held the Horned Frogs to 29 percent shooting.
Karviar Shepherd led TCU (9-7, 0-4 Big 12) with 13 points.
The teams have met 22 times and TCU has won just two of those contests.