Alberto Bayo y Giroud (27 March 1892 – 4 August 1967) was a Cuban military commander of the Republican faction during the Spanish Civil War.

He was appointed as the 2nd Chief of Staff of the V Army Corps for the Battle of Brunete, Modesto, but the commander of the unit opposed this and Bayo was relieved.

He was going to be in charge of preparing a guerrilla column in the Sierra de Madrid, but finally the project was not carried out and Bayo spent most of the contest as a military attaché in the Ministry of War.

Bayo had contact in Mexico with prominent Latin American revolutionaries, and was associate and mentor of some, including Ernesto Che Guevara and Fidel Castro.

While it is not known if he continued contact with Soviet agents such as "Comandante Carlos Contreras" (Vittorio Vidali), both were present in Mexico at the same period.