It was the first win of the season for Idaho (1-2).
Connor Hill scored 12 points for Idaho.
Green Bay's Kam Cerroni scored 9 points, all on 3-pointers.
Idaho had a 19-9 scoring advantage off the bench and scored 11 fast-break points while keeping Green Bay off the board in that category.
Shooting guard Jaylen Nowell, ranked No. 45 in the ESPN 100, chose the Washington Huskies on Wednesday over California. As a junior he led Garfield Heights to a state championship and was named MVP of the tournament.
Donnie Tyndall has filed an appeal to reverse the 10-year show cause penalty he received from the NCAA in April for violations that occurred while he was coaching Southern Mississippi.
Top-50 prospect Jaylen Nowell committed to Washington on Wednesday. Nowell, a shooting guard, is No. 45 on the ESPN 100.