The Tri-Valley Girls Varsity Water Polo Tournament is an annual competition held in Pleasanton, California, featuring high school varsity water polo teams from the Tri-Valley region and beyond. Established to promote competitive water polo among local schools, the tournament brings together teams primarily from Pleasanton, Dublin, Livermore, and neighboring areas, fostering athletic development and regional sportsmanship.

The tournament takes place in October, aligning with the high school water polo season, and is hosted at local venues such as Amador Valley High School and Foothill High School. Over the years, it has become a key event for girls' varsity teams, offering a platform for players to showcase their skills and compete at a high level.

The Tri-Valley tournament has seen growth in both participation and prestige, serving as a preparatory stage for teams aiming for league championships and CIF playoffs. In addition to the competitive spirit, it emphasizes camaraderie and the growth of water polo in the region, supporting young athletes in their pursuit of excellence in the sport.