The state treasurer of California is a constitutional officer in the executive branch of the government of the U.S. state of California. Thirty-five individuals have held the office of state treasurer since statehood. The incumbent is Fiona Ma, a Democrat. The state treasurer's main office is located in the Jesse M. Unruh State Office Building in Sacramento.

The government of California is the governmental structure of the U.S. state of California as established by the California Constitution. California uses the separation of powers system to structure its government. It is composed of three branches: the executive, consisting of the governor of California and the other constitutionally elected and appointed officers and offices; the legislative, consisting of the California State Legislature, which includes the Assembly and the Senate; and the judicial, consisting of the Supreme Court of California and lower courts. There is also local government, consisting of counties, cities, special districts, and school districts, as well as government entities and offices that operate independently on a constitutional, statutory, or common law basis. The state also allows direct participation of the electorate by initiative, referendum, recall and ratification.