Marquis of Alorna was a Portuguese title of nobility granted, on 9 November 1748, by King John V of Portugal, to D. Pedro Miguel de Almeida Portugal e Vasconcelos, 3rd Count of Assumar and 44th viceroy of India.
Originally, on 24 March 1744, the title was granted to him as Marquis of Castelo Novo but, due to his victories in India, it was changed, in 1748, to Marquis of Alorna, a town in Portuguese India.
The House of Alorna was later inherited by the Marquesses of Fronteira, once the last Marchioness of this line, Leonor Benedita Maria de Oyenhausen de Almeida (1776–1850), married João José Luis Mascarenhas Barreto (1778–1806), 6th Marquis of Fronteira.