The F Market & Wharves line is one of several light rail lines in San Francisco, California. Unlike most other lines in the system, the F line runs as a heritage streetcar service, almost exclusively using historic equipment both from San Francisco's retired fleet as well as from cities around the world. While the F line is operated by the San Francisco Municipal Railway (Muni), its operation is supported by Market Street Railway, a nonprofit organization of streetcar enthusiasts which raises funds and helps to restore vintage streetcars.

Heritage streetcars or heritage trams are a part of the efforts to preserve rail transit heritage. In addition to preserving street-running rail vehicles, heritage streetcar operations can include upkeep of historic rail infrastructure. Working heritage streetcars are closely related to the growing global heritage railway movement and form a part of the living history of rail transport.