La Reina High School of Thousand Oaks and Westlake High School came in second and third.
The 2018 decathlon was held over the past two Saturdays at Pacifica High School in Oxnard.
It is the second year in a row that Calabasas High has won the competition. The school will advance to the state Academic Decathlon, which will be held in March in Sacramento. The winning California team moves on to the national competition.
Ventura County teams have made it to the nationals six times, placing second in 2000 and 2002, and taking first place in 1999, 2003, 2008 and 2009.
An awards ceremony took place Monday in Oxnard.
The Calabasas High A Team includes coach Tyler Lee and students Shirin Ehyaei, Kerr Gebreselassie, Allyson Gerard, Vidish Gupta, Tobias Hirth, Kousha Keramati, Daniel Mizin, Timothy Motte and Skylar Steinman.
The Academic Decathlon gives high school students in the region a chance to compete against their peers. Students compete in 10 academic events that cover subjects ranging from art to economics.
The United States Academic Decathlon is the premier scholastic competition for students from public and private high schools across the country.
The competition includes students from all academic backgrounds. A team consists of nine full-time students from the 9th through 12th grades at the same high school. Each team comprises three students whose grade point average falls into the “A” category, three students in the “B” category and three students in the “C” category.