Thomas Hellyer (1811–18 March 1894) was an English architect of the mid-Victorian era. He was based on the Isle of Wight and was "the leading Island-based architect of the period", but his works can also be found on the mainland—principally in Hampshire—but also further afield. Described by Pevsner as a "very individualistic" and "remarkable" architect, his output included churches, houses, schools and hospitals across the island, during a period of rapid urban development. Many of his buildings have listed status and he "made important contributions to the appearance of the city" of Portsmouth through his extensive work in the area.