James Ennis contributed 16 points and six assists, and Eugene Phelps added 11 points as the 49ers (3-1) bounced back from a loss to San Diego State. Long Beach State won at No. 17 Pittsburgh last week.
The 49ers led by 23 points with 5 1/2 minutes to go before the Broncos closed the game on a 17-4 run.
Freshman Anthony Drmic led Boise State (3-1) with 20 points, including five 3-pointers. Kenny Buckner scored 12 of his 14 points in the first half for the Broncos, whose only lead was after the game’s first basket.