"I think they have an opportunity to compete for a national championship," said Baker, who will join the Cowboys after he finishes the semester at Clemson next month. "I'm hoping I can come in there and help."
Oklahoma State coach Mike Gundy gave Baker an enthusiastic welcome on Twitter, calling him "another game changer in the program."
Baker started three games for the Tigers in 2015 and intercepted two passes, but he missed all of the past season after suffering a torn ACL in the spring.
His arrival figures to boost an Oklahoma State secondary that doesn't have another cornerback with starting experience. Earlier this spring, the Cowboys bumped three-year starter Ramon Richards from corner to free safety.
The Cowboys were ranked 10th in ESPN's most recent Way-Too-Early Top 25 for the 2017 season.
Oklahoma State will hold its spring game on Saturday.