The 84th Mixed Brigade (Spanish: 84.ª Brigada Mixta), was a mixed brigade of the Spanish Republican Army in the Spanish Civil War. It was formed in March 1937 with battalions of the Iron Column (Spanish: Columna de Hierro) and was disbanded after the tragic events at Mora de Rubielos when 46 soldiers were shot by firing squad in a decimation following the brigade's Battle of Teruel December combats in harsh winter conditions.