Bernardino Luis Machado Guimarães (Rio de Janeiro, Brazil, 28 March 1851 - Oporto, 29 April 1944), was a famous Portuguese political figure.

Machado became Minister for Foreign Affairs in the first provisional government after the republican revolution of 1910, and later ambassador to Brazil.

He became President of Portugal in 1915, but left office two years later, in 1917, to be replaced by General Sidónio Pais, a dictator. He served as Prime Minister from 10 February to 23 May 1921. Once again, in 1925, he achieved presidential office only to be overthrown a year later (1926) by dictator António de Fragoso Carmona. The country remained under a military, then civilian, dictatorship until 1974.

He was father-in-law of famous writer Aquilino Ribeiro.