Mariners Harbor is a neighborhood located in the northwestern corner of New York City, USA's borough of Staten Island.

The neighborhood owes its name to the fact that, during the 19th Century, oysters and other seafood products were harvested at the site from the Kill Van Kull and the Arthur Kill, which form, respectively, the neighborhood's northern and western borders. This activity declined due to pollution during the 20th Century, and today only the Mariners Harbor Yacht Club remains as a reminder of the community's maritime past.

One of the stations on the North Shore branch of the Staten Island Railway was both located in and named after the neighborhood, within which was also found three other stations along the line, at Lake Avenue, Harbor Road, and Arlington (passenger service on this line was discontinued in 1953).

In the 1920s and 1930s the area became home to many Italian-Americans, who still comprise a significant percentage of its population. The neighborhood was permanently transformed, however, in the late 1940s, when the New York City Housing Authority erected a public housing project in the heart of the community, which then soon became predominantly African-American and later, also Hispanic. This housing development, like many others on Staten Island and for that matter, citywide and even nationwide, was hit hard by the crack cocaine epidemic which began in the mid-1980s; this further increased the area's crime rate, which had been high since the mid-1960s.

Immediately to the south of the housing project is a shopping center once dominated by an outlet of Major's Department Stores; in 1968, this outlet attracted a swarm of media attention when a white boy, believed to be approximately eight years old, was accosted in the store's rest room by several older African-American youths, one of whom produced a knife and castrated the victim. Another dubious "landmark" of the neighborhood's past is the Conca d'Oro Motel; opened across Forest Avenue from the aforementioned shopping center in the late 1970s, its owners, who had reputed Mafia connections, eventually leased the property to the city, which used it to house welfare mothers and their children. In the 1990s the building was sold and its name changed to Angels By The Sea II (the new owners also maintained another property, used for the same purpose, located in the Sheepshead Bay section of Brooklyn, named Angels By The Sea - thus accounting for the name of the Mariners Harbor property in light of its being situated 0.84 miles [1.35 km] from the nearest shoreline). Intense local opposition ultimately forced the facility to close, and the structure itself was demolished in the summer of 2004; various retail establishments are expected to take its place.

Nearby, and sometimes reckoned as part of Mariners Harbor, is Port Ivory — so named because it was long the site of a soap factory operated by Procter & Gamble (which closed it in 1991). Another point of interest in Port Ivory is the Howland Hook Marine Terminal, where a large volume of consumer goods is unloaded off ships and transferred to trucks (and formerly, freight trains that operated on the North Shore branch of the Staten Island Railway). The Staten Island side of the Goethals Bridge is also located here, as is the island's lone mobile home park.

The ZIP Code for Mariners Harbor is 10303.