Emmett collected 20 of his points in the second half as the Red Raiders (16-8, 6-7 Big 12) won for just the fifth time in 16 meetings with the Cowboys since the formation of the conference in 1996.
"I thought that Andre Emmett played the best all-around game of basketball that I have seen in the last two years," said Red Raiders Coach Bob Knight. "In every phase, he was a factor."
Emmett also contributed nine rebounds, four assists, and six steals.
Texas Tech improved to 2-5 in conference road play and recorded a much-needed quality win in an attempt to bolster its case for an NCAA Tournament at-large berth.
Melvin Sanders led Oklahoma State with 17 points, but the Cowboys (20-6, 9-4) lost for the third time in four games.
"We softened up and we got stagnant (in the second half)," said Cowboys Coach Eddie Sutton. "It is pretty hard to win when your top three scorers (Sanders, Tony Allen, and Victor Williams) go 14-for-40."