The Brooklyn-Battery Tunnel is a toll road in New York City which crosses under the East River at its mouth and connects the Boroughs of Brooklyn and Manhattan, passing under but providing no access to Governors Island. It consists of twin tubes, carrying an aggregate of four traffic lanes, and at 9,117 feet (2,779 meters) is the longest underwater tunnel in North America. It was opened to traffic in 1950.

The battery referred to in the tunnel's name refers to Battery Park and Castle Clinton, the former fortification at the southern tip of Manhattan.

The tunnel is owned by the City of New York and operated by the Triborough Bridge and Tunnel Authority, an affiliate agency of the Metropolitan Transportation Authority.

As of March 13, 2005, the crossing charge for a two-axle passenger vehicle is $4.50 in each direction, with a $.50 discount for E-ZPass users.

The tunnel carries Interstate 478, but that route is not signed.