California Southern Baptist Convention is a fellowship of about 450,000 members in approximately 1,800 language and multi-ethnic congregations that cooperate with the Southern Baptist Convention, the largest Protestant denomination in America. Each week throughout California 60 language groups and almost 100 ethnic groups are represented in congregations throughout the convention.

California Southern Baptist Convention is one of 39 state Baptist conventions and fellowships that work in all 50 states and American territories. Each state convention is independent of, but cooperates financially in, the work of the SBC. CSBC and the SBC share a common bond of basic biblical beliefs and a commitment to proclaim the Gospel of Jesus Christ to the entire world.

California Southern Baptist Convention also refers to its annual meeting held in November to conduct business.