The M Ocean View is a Muni Metrolight rail line in San Francisco, California. It was one of San Francisco's streetcar lines in the early 20th century, and was partially converted to modern light-rail operation with the opening of the Muni Metro system in 1980. While many streetcar lines were converted to buses after World War II, the M Ocean View remained a streetcar line due to its use of the Twin Peaks Tunnel.