The 2002–03 Oklahoma State Cowboys basketball team represented Oklahoma State University as a member of the Big 12 Conference during the 2002–03 NCAA Division I men's basketball season.
They were led by 13th-year head coach Eddie Sutton and played their home games at Gallagher-Iba Arena in Stillwater, Oklahoma.
The Cowboys lost to Missouri in the quarterfinals of the Big 12 tournament.
The team received an at-large bid to the NCAA tournament as the No.
Oklahoma State beat Penn in the opening round, but lost to No.