Morrisania (/ˌmɒrɪˈseɪniə/ MORR-i-SAY-nee-ə) is a residential neighborhood in the southwestern Bronx, New York City, New York. Its boundaries are the Cross-Bronx Expressway to the north, Crotona-Prospect Avenue to the east, East 161st Street to the south, and Webster Avenue to the west. Third Avenue is the primary thoroughfare through Morrisania. Its name derives from the Manor of Morrisania, once the entire South Bronx.

The name derives from the Manor of Morrisania, the vast 2,000 acre estate of the powerful and aristocratic Morris family, who at one time owned most of the Bronx as well as much of New Jersey. The family includes Lewis Morris, 4th Lord of the Manor, and a signer of the United States Declaration of Independence, and Gouverneur Morris, penman of the United States Constitution. Both are buried in the crypt at St. Ann's Church of Morrisania. Today the name is most commonly associated with the neighborhood of Morrisania, which is only a small corner of the original Morrisania.