The 8th Mixed Brigade () was a mixed brigade of the Spanish Republican Army in the Spanish Civil War. It was formed at the beginning of the Defence of Madrid in early spring 1937 with battalions of the "Carabineros" corps and it remained in Madrid all along the war. Its first commander was "Carabineros" Lt. Colonel Enrique del Castillo Bravo who was succeeded by "Carabineros" Commanders Emeterio Jarillo Orgaz and José Casted Sena.