Smart opted to return to school instead of declaring for the June 27 draft. ESPN's Chad Ford had him ranked second overall on his Big Board.
Smart will officially announce his decision Wednesday in a news conference at the school.
The 6-foot-4, 225-pound Smart averaged 15.4 points and 4.2 assists per game while shooting 40 percent from the field in his first season with the Cowboys.
Smart was chosen as the Big 12 player of the year and freshman of the year. Oklahoma State went 24-9 and lost to Oregon in its NCAA tournament opener.
Smart's decision was reported earlier Tuesday by Yahoo! Sports.
Information from The Associated Press was used in this report.