Rothesay is a town located in Kings County, New Brunswick, Canada. It is adjacent to the City of Saint John along the Kennebecasis River.

Located along the lower Kennebecasis River valley, Rothesay borders the city of Saint John to the southwest, and the neighbouring town of Quispamsis to the northeast. It is served by a secondary mainline of the Canadian National Railway, though there is no longer any passenger service on the line.

The town developed first as a shipbuilding centre and later as a summer home community for Saint John’s wealthy elite with the arrival of the European and North American Railway in 1853. There is a commonly known story that the new town was named in honour of the visiting Prince of Wales, later King Edward VII, in 1860 because the area was said to have reminded him of Rothesay, on the Isle of Bute, in Scotland.