The Lenox Library was a library incorporated and endowed in 1870. It was both an architectural and intellectual landmark in Gilded Age–era New York City. It was founded by bibliophile and philanthropist James Lenox, and located on Fifth Avenue between 70th and 71st Streets on the Upper East Side of Manhattan. Renowned architect Richard Morris Hunt designed the building, which was considered one of the city's most notable buildings, until its destruction in 1912.

James Lenox was an American bibliophile and philanthropist. His collection of paintings and books eventually became known as the Lenox Library and in 1895 became part of the New York Public Library.