The 1919 Soviet invasion of Ukraine occurred in 1919 when the Red Army of the Russian SFSR invaded Ukraine amid the Russian Civil War and the Ukrainian War of Independence.
After the surrender of the German Empire at the end of World War I in November 1918, the Bolsheviks declared the Treaty of Brest-Litovsk null and void, and, on 18 November 1918, the Ukrainian Reds launched an offensive. In December, the Ukrainian Reds attacked Chernihiv, Sumy, Kharkiv, and Kyiv, attacking the Ukrainian People's Republic forces while maintaining neutrality towards the withdrawing Imperial German Army forces. On 1-2 January 1919, a Bolshevik uprising broke out in Kharkiv, and, on 3 January, the Red Army entered the city, and the Bolshevik provisional government of the Ukrainian SSR relocated from Belgorod to Kharkiv.
From 6 January to 9 March 1919, the 15,000-strong Red Army in Ukraine launched an offensive against the UNR with support from socialist rebels and Red guerrillas, defeating Petro Bolbochan's 20,000 Ukrainian nationalists in left-bank Ukraine before crossing the Dnieper and taking Kyiv on 5 February 1919. The directorate of the UNR relocated to Vinnytsia, and local Ukrainian nationalists established short-lived republican governments in local rebellions against Bolshevik occupation. On 14 March, the Soviet offensive continued, attacking the UNR in the west, the French Army in the southwest, and the White Army in the south. By then, the Reds had been reinforced to 50,000 troops, and, by mid-April, the Reds defeated the UNR army and came into contact with Polish forces in Volhynia and Galicia amid the Polish-Ukrainian War.
In the south, the Reds captured Perekop from the Whites and overran most of the Crimea, and Sevastopol fell on 29 April 1919, a few days after the French Navy and Greeks evacuated the city. The Reds went on to occupy the coast of the Sea of Azov from Henichesk to Mariupol, while, in the southwest, the Reds cleared the land from Transnistria to Tiraspol, clearing the war for an advance on Chisinau in Moldova. However, the Reds badly outstretched their resources and soon found themselves on the defensive on all fronts. In mid-June 1919, a White Army advance forced the Reds out of Crimea, and, by August 1919, almost the whole Ukraine was lost as the Whites captured Kyiv.