St. Mary's Church is an historic Roman Catholic church complex at 14 William Street (Spring Street at Memorial Boulevard) in Newport, Rhode Island within the Diocese of Providence.
The complex includes three buildings: the brownstone Gothic Revival church, the parish house, formerly a school, and a convent. The church was built in 1848-52, to a design by renowned Brooklyn architect Patrick C. Keely. In 1865 the school was built directly east of the church, also designed by Keely. During the 1880s, the church built two new buildings, niether of which are included in this nomination. A convent was built in 1880-81, designed by local architect Dudley Newton. In 1991 that building was moved from its site at Spring and Gidley Streets to its current location at 398 Thames Street, where it serves as the Admiral Fitzroy Inn. Dudley also designed a rectory in 1886, which burned in 1921. A new rectory, designed by Ambrose J. Murphy, was built on the same site in 1924-25. In 1937, both church and school were altered by architect John F. Hogan. In 1967, in order to comply with Vatican II, East Providence architect Milton R. Kenyon further altered the church.
The parish congregation was founded in 1828, and was the first Roman Catholic parish established in the state. In 1953 Senator John F. Kennedy and Jacqueline Bouvier were married at St. Mary's.
The church was added to the National Register of Historic Places in 2008.