Lucio Costa (27 February 1902 - 13 June 1998) was a Brazilian architect and urban planner.

Costa was born in Toulon, France. Educated at the Royal Grammar School, Newcastle upon Tyne, England and at the Collège National in Montreux, Switzerland, until 1916, he graduated as an architect in 1924 from the National School of Fine Arts (Escola Nacional de Belas Artes) in Rio de Janeiro. After some early works in the eclectic manner, he adopted Modernism in 1929. In 1930 Costa established a partnership with Russian-born Brazilian architect Gregori Warchavchik, and also became the Director of the National School of Fine Arts where he had studied. Even though he found students eager to be taught in the "new style," his ruthless administration won him the opposition of the faculty and student body, and Costa eventually had to resign after a year in office. He joined the newly-created SPHAN (Servico do Patrimônio Histórico e Artístico Nacional - National Service of Historic and Artistic Heritage) in 1937 under Rodrigo Melo Franco de Andrade. He remained at the National Heritage Service until retirement, acceding to the top post of director, where he was followed by his granddaughter Maria Elisa Costa. During his tenure as regional and then national director, he became involved in numerous controversial decisions (see Controversies).

Costa became a figure associated with reconciling traditional Brazilian forms and construction techniques with international modernism, particularly the work of Le Corbusier. His works include the Brazilian pavilion at the New York World's Fair of 1939 (designed with Oscar Niemeyer), the Parque Guinle residential complex in Rio of 1948, and the Hotel do Park São Clemente in Nova Friburgo of 1948. Among his major works are also the Ministry of Education and Health, in Rio (1936–43), designed with Le Corbusier, Oscar Niemeyer, and Roberto Burle Marx, among others, and the Pilot Plan of Brasília, a competition winner designed in 1957 and mostly built in 1958-1960.