Bishop Stephen Peter Alencastre, SSCC (born Estêvão Pedro de Alencastre; November 3, 1876 – November 9, 1940) was a bishop of the Roman Catholic Church who served as the fifth and last Vicar Apostolic of the Vicariate Apostolic of the Hawaiian Islands (now the Diocese of Honolulu). He was also an apparent titular bishop of Arabissus.
