US Post Office-Tonawanda is a historic post office building located at Tonawanda in Erie County, New York, United States.

It was designed and built 1939–1940, and is one of a number of post offices in New York State designed by the Office of the Supervising Architect of the Treasury Department under Louis A. Simon.

The building is in the Colonial Revival style and features a central pavilion crowned by a cupola and flanked by end pavilions with gable roofs.

The interior once featured a mural by Symeon Shimin, but it was removed and has disappeared.

This article about a historic property or district in Erie County, New York, that is listed on the National Register of Historic Places, is a stub.