Augusto Barcía Trelles (Vegadeo, 1881–Buenos Aires, 1961) was a Spanish politician and was the Prime Minister of Spain from May 10, 1936 to May 13, 1936. He was also a lawyer and a Freemason.

In the Congress he was against the law of the terrorism of Maura (1908). He was a deputy in the Cortes from 1916 to 1923. During the II Republic he affiliated himself with the Republican Left, to which he headed in the Cortes of 1935. He was the defender of Luis Companys Jover and his companions of the Catalan Generalitat by his participation in the rising against the Republic of October 1934. After the triumph of the Popular Front in the elections of February 1936, he was named minister of State in the governments of Manuel Azaña, Santiago Casares Quiroga, Diego Martínez Barrio and José Giral. After the end of the Spanish Civil War he fled to Argentina.