Euzko Gudarostea (modern spelling: Eusko Gudarostea, "Basque army") was the name of the army commanded by the Basque Government during the Spanish civil war. It was formed by Basque nationalists, socialists and communists under the direction of lehendakari José Antonio Aguirre and coordinating with the army of the Second Spanish Republic. It fought the troops of Francisco Franco during 1936 and 1937. It surrendered to the Italian Corpo Truppe Volontarie at Santoña (province of Cantabria), while the rest of the Republican army kept fighting until 1939. This event is referred as the Treason of Santoña by some Spanish leftists.
The Basque word for a soldier, gudari (plural gudariak), is a neologism (from guda, "war", thus meaning "warrior" literally). The Standard Basque word is the Romance-derived soldadu. Like other Basque nationalist neologisms (ikurriña, lendakari), the meaning of gudari has been restricted to Basque concepts. The Basque word for an army is the Romance-derived armada.
The members of the Basque militant ETA consider themselves gudariak continuing the struggle of the Civil War Basque soldiers. This is contested by those war veterans that support the Basque Nationalist Party (PNV), Spanish Socialist Workers' Party or Communist Party.