Tharpe provided 19 points and five assists as the Jayhawks (22-6, 13-2 Big 12) posted a fourth straight win.
Wayne Selden and Andrew Wiggins each netted 15 points.
Joel Embiid had a double-double of 12 points and 13 rebounds for Kansas, which has either won or shared a conference title an NCAA-record 57 times.
The Sooners (20-8, 9-6) were led by Cameron Clark's 18 points.
Buddy Hield added 16.