London Nicole Breed is an American politician who is the 45th mayor of San Francisco, serving since 2018. She was supervisor for District 5 and was president of the Board of Supervisors from 2015 to 2018.

The mayor of the City and County of San Francisco is the head of the executive branch of the San Francisco city and county government. The officeholder has the duty to enforce city laws, and the power to either approve or veto bills passed by the San Francisco Board of Supervisors, the legislative branch. The mayor serves a four-year term and is limited to two successive terms. Because of San Francisco's status as a consolidated city-county, the mayor also serves as the head of government of the county; both entities have been governed together by a combined set of governing bodies since 1856.