On August 21, 2015, Fultz committed to the University of Washington.[6] He concluded his high school career as he recorded the Stags' single-season record for assists with 278 and led the team to their second consecutive conference championship.[2] At the McDonald's All-American Game on March 31, 2016, Fultz tallied 10 points, 6 rebounds, and 4 assists.[7] At the Jordan Brand Classic come April, Fultz accumulated 19 points in a 131–117 East team victory.[8] During the summer, he was selected to Team USA's FIBA Americas Under-18 roster.