Oregon State led by just one at 16-15 but the Beavers went on a 15-2 run, with seven points by Gabriella Hanson, to take a 31-17 lead and led the rest of the way. The Beavers built a 42-25 lead at halftime.
Deven Hunter scored 17 points and Hanson added 15 for Oregon State (19-9, 11-5 Pac-12), which has won seven straight and is tied with No. 20 Arizona State for third place in the conference. The Beavers host the Sun Devils next Sunday to conclude their regular season.
Kelsey Plum scored 26 points and Jazmine Davis added 19 to lead Washington (16-11, 9-7) which snapped a four-game winning streak.
After the game, the Huskies honored Mercedes Wetmore for Senior Day. The former Auburn-Riverside star started for Washington, but she went scoreless in the final home game of her career.