Alfredo Luís da Costa (24 November 1883 – 1 February 1908) was a Portuguese publicist, editor, journalist, shop assistant and salesman who was part of the Portuguese Carbonária and a Mason, best remembered for being one of the two assassins (with Manuel Buíça) credited in the assassination of King Carlos I of Portugal and the Prince Royal, Luis Filipe, during the events that became known as the 1908 Lisbon Regicide (on 1 February 1908), ultimately leading to his death.