Michael Porter Jr. will attend Missouri for his freshman season.
Porter had previously signed with Washington but asked for his release after they fired Lorenzo Romar as head coach and his father as assistant coach.
Porter is the top recruit in the incoming class of 2017 and is widely expected to be the top pick in the 2018 NBA Draft.
Porter played his final season of high school basketball for Nathan Hale High School in Seattle where he was coached by Brandon Roy.
Missouri hired Cuonzo Martin this month.
"Last week everything changed for me regarding my college basketball decision. Realizing I would no longer have the opportunity to play for Coach Romar, I've taken the past seven days to give great consideration to my future.
"After a lot of thought, prayer, and talking with my family, I'm excited to announce that next year I will be attending the University of Missouri!
"I'm looking forward to the year ahead with Coach Cuonzo and my new teammates... Together we hope to restore the atmosphere at Mizzou Arena."