The Ocean Shore Railroad was a railroad intended to run between San Francisco and Santa Cruz, California. The 1906 San Francisco Earthquake and financial difficulties prevented the railroad from completing construction. It operated as two discontinuous segments from 1905 to 1920: San Francisco to Tunitas Glen, and Swanton to Santa Cruz.

The first attempts to construct a railroad between San Francisco and Santa Cruz began as early as 1870, with the organization of the San Francisco, Santa Cruz, & Watsonville Railroad Company. The railroad was to be funded via public money, however, most records cut off around 1872 so it is speculated that two other railroads had taken away the public interest.

Incorporated in 1875, the railroad was funded by residents of San Mateo County in order to construct a line between San Francisco and Santa Cruz via Spanishtown (now Half Moon Bay). The railroad hired a surveying team, which published a final report in March 1876 detailing the feasibility. However, it is assumed the railroad went under due to lack of finances, as no other paper traces are found.

Incorporated in September 1879, the San Francisco & Ocean Shore Railroad Company was conceived to be a narrow-gauge railway running between San Francisco and Santa Cruz. In Santa Cruz, the line would have connected with the Santa Cruz Railroad and allowed for the exchange of freight. The San Francisco County Board of Supervisors granted the railroad permission to construct trackage from Fulton and Larkin Streets, and down away from the city, however construction was stalled after multiple business owners along the route launched lawsuits.

Said lawsuits took away time and money, as by 1881 the railroad had promised to construct a line to the border of San Mateo County, but in reality had not laid a single rail. Between 1880 and 1881 the railroad attempted to increase revenue by taking out mortgages and distributing stocks. In 1881, the Santa Cruz Railroad had gone bankrupt, which largely cut off a lot of funding for the San Francisco & Ocean Shore Railroad as some investors had put much of their fortune into the Santa Cruz Railroad too. Plans were redrawn to enter Santa Cruz.

In around January 1881, the railroad was reorganized to become a standard gauge line, and filed for incorporation to construct tracks through Half Moon Bay. Around May 1881, various rumors were circulating around San Francisco in relation to the San Francisco & Ocean Shore Railroad. These rumors included that the line was going to extend to Santa Barbara, and that it was secretly going to be a part of a new Atchison, Topeka and Santa Fe Railway transcontinental route along the coast.

After the Southern Pacific Railroad and the Atchison, Topeka and Santa Fe Railway had ended some bitter rivalries in December 1881, on Christmas Eve it was stated that the San Francisco & Ocean Shore Railroad's multi-state plan (involving the California Central Railway) was merely a ploy to scare the Southern Pacific Railroad into reducing the cost of freight switching at junctions with the Atchison, Topeka, & Santa Fe. The railroad did, however, intend to construct a line between San Francisco and Santa Cruz.

The announcement had dire consequences, and in early 1882 the San Francisco County Board of Supervisors voted to delay the acceptance of the franchise to allow the running of the railroad in the city itself. By November 1882, the San Francisco & Ocean Shore Railroad had indefinitely ceased development of the line, and after numerous economic crashes, the line was abandoned without a single track laid.