Polish–Ukrainian conflict (1939–1947)

Polish-Ukrainian conflict
	Part of the Eastern Front of World War II and the Polish resistance movement in World War II
Date	1939–1947 (minor fighting continued until 1948)
Location	South-eastern Poland (Kresy)
Result	See § Aftermath
Territorial; changes	Establishment of the Polish–Soviet border on the Curzon Line; Population exchange between Poland and Soviet Ukraine; Liquidation of UPA remnants in the post-war Poland after Operation Vistula;
Belligerents
Second Republic of Poland (1939); Polish Underground State (1941–1944); Polish People's Republic (1944–1947); Soviet Union (1943-1947)	OUN (1939); Ukrainian Insurgent Army (1941–1947); Ukrainian People's Revolutionary Army (until 1943); Reichskommissariat Ukraine (Ukrainian Collaborators 1941–1944)
Commanders and leaders
Second Polish Republic Stefan Dembiński; Home Army: Stefan Rowecki; Leopold Okulicki; Władysław Kochański (WIA); Henryk Cybulski; Stefan Czerwiński; Kazimierz Bąbiński; Jan Kotowicz; Kazimierz Filipowicz; Antoni Rychel †; Zdzisław Ostromęcki †; Stefan Kwaśniewski; Franciszek Studziński; Władysław Herman; Henryk Krajewski; Józef Biss; Peasant Battalions: Stanisław Basaj †; National Armed Forces (1943–1945) Antoni Żubryd; Polish People's Republic (1944–1947): Bolesław Bierut; Stefan Mossor; Franciszek Jóźwiak; Karol Świerczewski †; Michał Rola-Żymierski; Marian Spychalski; Soviet Union Nikolai Vatutin †; Timofei Strokach; Pavel Sudoplatov; Vladimir Trubnikov; Vasyl Ryasnoy; Sergey Savchenko; Nikolai Kovalchuk; Viktor Drozdov; Alexei Asmolov;	OUN (1939): Andriy Melnyk; Wilhelm Canaris (German Uprising advocate); Ukrainian Insurgent Army (1941–1947) Dmytro Klyachkivskyi; Maryan Lukasevych †; Vasyl Kuk; Vasyl Sydor; Oleksandr Hasyn; Petro Oliynyk; Ivan Lytvynchuk; Oleksandr Lutskyi; Mykola Kozak; Mykola Lebed; Vasyl Halasa; Stepan Stebelskyi; Yuriy Stelmashchuk ; Maksym Skorupskyi; Mykhailo Soltys; Ivan Shpontak; Volodymyr Shchyhelskyi ; Myroslav Onyshkevych ; Ukrainian People's Revolutionary Army (until 1943): Petro Dolmatyuk; Ivan Mitrynga †;
Units involved
Second Republic of Poland (1939) Polish Armed Forces; Home Army (1941–1945) 27th Volhynian Infantry Division; Polish Self-Defence Division; Peasant Battalions (1943–1945) Ryś Battalion; National Armed Forces (1943–1945) „Zuch” Battalion; Polish People's Republic (1944–1947) Polish People's Army; People's Army (Poland); Operational Group "Rzeszów"; Operational Group "Vistula"; Ministry of Public Security (Poland); Citizens Militia; Soviet Union NKVD; Red Army; Internal Security Corps; Ministry of State Security (Soviet Union); Soviet Partisan Group in Volhynia;	OUN (1939): Ukrainian Legion; Ukrainian Insurgent Army (1941–1947): UPA-West; UPA-North; UPA-South; Ukrainian Collaborators (1941–1945): Ukrainian Schutzmannschaft Battalions; 14th Waffen Grenadier Division of the SS (1st Galician); 4th SS Police Regiment (Galician); 5th SS Police Regiment (Galician) ; Ukrainian Auxiliary Police; Ukrainian Legion of Self-Defense; Abwehr (1939); Ukrainian People's Revolutionary Army (until 1943)
Strength
Second Republic of Poland (1939): Unknown; 2,500 troops; Home Army: 40,000–50,000 troops; Polish People's Republic: 20,000–30,000 troops;	OUN (1939): 7,729 troops; Ukrainian Collaborators (1941–1945): 50,000–70,000 troops; Ukrainian People's Revolutionary Army 3,000–5,000; Ukrainian Insurgent Army (1941–1947): 25,000–100,000 troops;
Casualties and losses
1945–1947:; 8,100 killed; 5,000 killed	1945–1947:; 8,700 killed
	See civilian casualties: Aftermath

The Polish–Ukrainian conflict took place from 1939 to 1947. It was fought primarily between irregular Ukrainian and Polish units, with limited participation by Soviet partisans and the Red Army, as well as Romanian, Hungarian, German and Czechoslovak armed formations. Fighting was concentrated in south-eastern Kresy region (today Western Ukraine) of the German-occupied Second Polish Republic.

The occupation of Poland by Germany and Soviet Union in September 1939 led to demands by Ukrainian nationalists for a new Ukrainian state which would include the Polish territories of Eastern Galicia and Wołyń (Volhynia).