"It wasn't an easy decision because the fans showed me so much...." said Wiggins, as reported by the Associated Press. "I just wish I had more time. College goes by so fast, I can see why people stay all four years."
The 19-year-old, 6-foot-8 forward averaged 17.1 points a game for the Jayhawks (2nd seed), who were eliminated in the second round of the NCAA tournament by the 10th-seeded Stanford Cardinal.
Wiggins could go first overall in the June 26 NBA draft.
His teammate, center Joel Embiid, has yet to announce his intentions. Embiid was unable to play in the NCAA tournament with a stress fracture in his back, but projects to be a top-three pick if healthy.
A number of high-level prospects have also declared including Tyler Ennis from Syracuse and Noah Vonleh from Indiana, along with Kyle Anderson and Zach LaVine from UCLA.
Duke's Jabari Parker, Oklahoma State's Marcus Smart and Aaron Gordon of Arizona also haven't made an official decision. Kentucky's Julius Randle and Willie Cauley-Stein are still active in the Final Four, although Cauley-Stein is dealing with an ankle injury.
Creighton's Doug McDermott, as a senior, will also be in the draft pool.
Early entry candidates can withdraw from the draft by June 16, as long as they don't hire an agent to represent them.
To have a shot at Wiggins, the Lakers will need to win a top-three pick in the lottery.