Afonso Augusto da Costa, GCTE, GCL (Portuguese pronunciation: [ɐˈfõsu ˈkɔʃtɐ]; born in Seia, 6 March 1871; died in Paris, 11 May 1937) was a Portuguese lawyer, professor, and republican politician.
Costa was the leader of the Portuguese Republican Party, and he was one of the major figures of the Portuguese First Republic. He was a republican deputy in the Chamber of Deputies during the last years of the monarchy. After the proclamation of the republic, he was Minister for Justice during Teófilo Braga's short-lived provisional government, which lasted from 5 October 1910 to 3 September 1911.
During this period, Costa signed the controversial laws which expelled the Jesuits from Portugal, abolished all the religious orders, and established the separation of church and state. These things made him a symbol of the anticlericalism of the First Republic. Also, he was instrumental in the passage of many other progressive laws, such as those concerning divorce, family relations, civil registry of marriage, leases of property, judicial reorganization, industrial accidents, and censorship of the press.