The Army of the Po (Italian Armata del Po), numbered the Sixth Army (6a Armata), was a field army of the Royal Italian Army (Regio Esercito) during World War II (1939–45).
When it was initially formed on 10 November 1938 under the command of General Ettore Bastico, it comprised three corps: the Corpo d'Armata Autotrasportabile (Motor Transportable Corps), consisting of three divisions; the Corpo d'Armata Celere (Fast Corps), consisting of three celeri divisions; and the Corpo d'Armata Corazzato (Armoured Corps), consisting of two motorised and two armoured divisions in the process of formation. These were the Ariete and Centauro armoured divisions and the Trento and Trieste motorised divisions. This formation was the brainchild of General Alberto Pariani, then Chief of the General Staff, who desired to combine armoured and motorised divisions into a potent force based in the Po valley and ready to move towards any of Italy's land borders at a moment's notice. By December 1938, Bastico had drawn up plans for concentrating the force around Tarvisio in the event of war with Austria or on a line from Udine to Trieste in the event of war with Yugoslavia.
In 1939, six Blackshirt battalions took part in the field manoeuvres of the Army of the Po. In the first half of 1940 the Centauro division was moved to Albania, where it took part in the Italian invasion of Greece later that year. During the Italian invasion of France (10–25 June 1940), the Army of the Po (minus the Centauro) was held in reserve.
In February 1941, the headquarters of the Army of the Po (Sixth Army) was transferred to southern Italy. On 1 March, the Armoured Corps became the XVII Corps and deployed to Albania as an infantry command. All three of the former corps of the Sixth Army took part in the invasion of Yugoslavia in April. In July 1943, the headquarters of the Sixth Army took charge of the defence of Sicily. The 6th Army suffered heavy losses against the Allies in July–August 1943 and withdrew to northern Italy for reorganization. It capitulated to the Germans upon the surrender of Italy in September 1943.