Samuel J.F. Thayer (1842–1893) was an American architect, notable for designing buildings such as the Providence City Hall and the Cathedral of St. George, as well as the town halls of Brookline, Stoughton, and Methuen, Massachusetts. He was part of the architecture firms, Martin & Thayer and Ropes & Thayer.

Providence City Hall is the center of the municipal government in Providence, Rhode Island. It is located at the southwest end of Kennedy Plaza at 25 Dorrance Street in Providence. The building was constructed between 1875 and 1878, and designed by Samuel J. F. Thayer in the Second Empire style. In 1975, the building was listed on the National Register of Historic Places. It is also a contributing structure to the broader Downtown Providence Historic District.