Prisoners of war during World War II faced vastly different fates due to the POW conventions adhered to or ignored, depending on the theater of conflict, and the behaviour of their captors. During the war approximately 35 million soldiers surrendered, with many held in the prisoner-of-war camps. Most of the POWs were taken in the European theatre of the war. Approximately 14%, or 5 million, died in captivity; out of these, 3 million fatalities were Soviets POWs, and one million, German POWs.

Early in World War II, Nazi Germany, overwhelmed by the number of POWs, released many, though some became used as forced labor. As the war progressed, POWs became strategic assets, increasingly used as forced labor, or considered an important leverage for reciprocal treatment. Within a few years of the war ending, most of POWs were repatriated, though notable exceptions persisted, with Axis POWs in Chinese and Soviet camps held into the 1950s.

The mortality rate was disproportionately high in the Eastern and Pacific theaters, where atrocities, forced labor, and starvation were common, especially for Soviet and Chinese captives under Axis powers and German POWs in Soviet hands. Axis POWs were treated very well by the Western Allies and very harshly by the USSR. Western Allied POWs generally experienced better conditions than most other belligerents, although their treatment by the Japanese was harsh.

Post-war trials, including the Nuremberg Trials, prosecuted violations of POW treatment, though public awareness of such crimes emerged much later, particularly in Germany, while in Japan and the USSR the issue is still mostly ignored. POWs of World War II were selectively depicted in popular culture, often romanticized in Western media through escape narratives like The Great Escape, while harsher realities, such as Soviet treatment of captives, or Axis treatment of non-Western captives, remain underrepresented.

History

Most prisoners, after being captured, spent the war in the prisoner of war camps. In the early phases of the war, following German occupation of much of Europe, Germany also found itself unprepared for the number of POWs it held. As a result of that, as well as for political reasons, it released many (particularly enlisted personnel) on parole (as a result, it released all the Dutch, the Danes, all Flemish Belgian, all Greeks, nine-tenths of the Poles, and nearly a third of the French captives; some, however, like Poles, were almost immediately forcibly conscripted as laborers). Later prisoners became valuable and were kept as guarantee of good treatment of the prisoners' kept by the other side, or directly used for hard (forced) labor. A small number were exchanged in prisoner exchanges, primarily between Italy and Germany and the Western Allies (approximately 6,000 Italian, 14,000 German, and 12,400 Allied POWs were exchanged in such a fashion).

The majority of POWs were released by the late 1940s. In most places they were warmly received by the populace, major exceptions included France, where society "preferred to forget about them", and the USSR, where they suffered from much discrimination. The last POWs of World War II were Germans and Japanese released from the USSR camps in 1956; some Japanese were held in China until 1964. A few exceptions include stories such as András Toma, considered the last POW of World War II released from captivity, who was discovered living in a Russian psychiatric hospital in 2000 and was returned to Hungary some fifty-six years after his capture.

Number of POWs

In mid-90s Simon MacKenzie observed that "Obtaining an exact figure for the number of POWs [in WWII] is made virtually impossible by the inexactness or unavailability of the records kept by many of the belligerents". In some cases, where entire countries surrendered (for example, Belgians), most if not all soldiers who were not killed in action were captured at some point during the fighting, but many were quickly released unofficially; while others were imprisoned for years. Different estimates may or may not count all such groups as POWs. Likewise, German and Japanese soldiers held after their countries surrendered at the end of the war often were not categorized as prisoners of war (see Japanese Surrendered Personnel, Disarmed Enemy Forces and Surrendered Enemy Personnel.).

MacKenzie cites the figure of 35 million following the 1960s estimate by German historian . That estimate, considered conservative by MacKenzie, has been repeated in more recent works (such as by Christian Gerlach in the mid-2010s). Bob Moore, who in his monograph focused on the European theater, gave an estimate of "more than 20 million", which he considered inflated with the number of Axis troops that surrendered after the war.

Consequently, the estimates of the number of prisoners by country or origin or capture can vary as well. With regards to nationality, some estimates include:

By country of origin:

American POWs taken in all theaters: 103,918 (2% of total). Out of that, 95,532 were held by Germans and 21,580-26,943 by Japanese. British and the British Commonwealth POWs taken in all theatres: 353,941 (9% of total); including at least 15,000 Indian soldiers from the British Indian Army in German and Italian hands. Out of that total number, 142,319-169,000 were captured by Germany and Italy. In mid-1943 Italians held 70,000 British troops (about 40,000 British and the rest from the Commonwealth territories). Japanese held 21,000- 21,726 Australian, 50,016 British, 1,691 Canadian, at least 60,000 Indian and 121 New Zealand prisoners. Belgians: the majority of the Belgian army, numbering between 600,000-650,000, was captured by the Germans; 225,000 were sent to POW camps while the rest were released. Within a year, 108,000 Flemish Belgians were released as well. Chinese POWs: Tens of thousands of Chinese soldiers were captured by the Japanese every year of the Second Sino-Japanese War (1937–1945); total estimates of POWs vary but a range of at least 750,000 to over a million has been suggested by scholars. Danish POWs: while the Germans quickly captured the Danish army following the German invasion of Denmark, the Danes were quickly released. In 1943 about 10,000 Danish soldiers were arrested again and imprisoned in Germany, but most were again released quickly. Dutch POWs: while the Germans quickly captured the Dutch army (c. 300,000 soldiers) following the German invasion of the Netherlands, the Danes were quickly released. However, over 10,000 were taken into custody later in several German actions. A small number of soldiers from Free Dutch Forces were also subject to becoming POWs in Germany upon capture at various stages of the war. 37,000 from the forces of the Dutch colonial empire were held by Japanese. Filipino POWs: held by Japanese: at least 62,000 Finnish POWs: held by the USSR: 900 during the Winter War;Finnish POW during the World War II, Viktor Konasov, North magazine ("Север") no. 11–12, 2002 2,377-3,500 during the Continuation War French POWs: held by Germany: estimates vary from 1,500,000, 1,800,000 to 1,900,000 following the fall of France, including about 100,000 colonial auxiliaries. 15,000 (12,000 French and 3,000 colonial auxiliaries) were briefly held by the Japanese following the Japanese coup d'état in French Indochina in March 1945. German POWs: held by the USA: 11,000,000 total (with 1,600,000 captured by the Americans, and 2,400,000 by the British). 425,000 in the USA territory; more than 400,000 in British and Commonwealth territory; 2.8 million held by Western custody by April 30, 1945 (and close to 7 million in the months after the war); approximately 3,000,000 held by the USSR. Small numbers were briefly held in France until the fall of France. 5,000 were transferred to the custody of Free French in 1943, effectively as hostages to prevent Axis executions of Free French and French Resistance members; that number grew significantly to over 200,000 in as the war progressed. Greek POWs: Following the capitulation of Greece, the whole Greek Army, numbering around 430,000 men, was declared to be prisoners of war, however almost all were almost immediately released. Some Greeks joined the Allies-affiliated Greek Armed Forces in the Middle East; an estimated 2,000 were subsequently captured and treated as British auxiliaries. Hungarian POWs: around 500,000 were held by the USSR Italian POWs: estimate of Italian POWs before the Italian surrender: 700,000. Out of these: held by USSR: 65,000. 154,000 were held in Britain and 400,000 were held by Britain in various locations by the time war ended. A small number initially, then over 50,000 later, were sent to the United States; others in various parts of the Commonwealth (such as India, Australia, South Africa and Kenya). Close to 20,000 if not more were captured by Greeks during the Greek-Italian War in 1940. 15,000 were transferred to the custody of Free French in 1943; that number later increased to over 35,000. An estimate for the number of new Italian POWs following the surrender was at 1,300,000; most - approximately one million - were interned by the Germans following Italian surrender; They were not recognized as POWs by the Germans. A small number were interned by the Japanese. An estimate of one million Italian POWs still held by various captors by the time war ended in 1945 has also been given. Early in the war British also captured "many thousands" of Italian colonial troops; who were quickly released after being assessed as having little military value. Japanese POWs: 35,000-50,000 held by the Western Allies;* 900,000 were captured by the Soviets. 560,000 to 760,000 were held by the USSR after Japan surrendered. Norwegian POWs: while the Germans quickly captured the Norwegian army following the German invasion of Norway, the Norwegians were quickly released. About 1,500 were arrested in 1943; about 1,000 were held until the end of the war. Small number of Norwegians fighting for the Allies in exile were occasionally captured as well throughout the war. Polish POWs: all POWs after invasion of Poland: estimates range 650,000-1,039,800 with the lower estimates based on number of soldiers held at POW camps and the higher, for all soldiers as well as similar groups (ex. policeman) taken into custody (many were quickly released). Out of these: 420,000-694,000 held by Germany (many were quickly released then forced to become forced laborers), and 125,000, 190,000 or 452 500 held by the USSR following the Soviet invasion of Poland. More Polish soldiers would be captured later in the war as Poland created several armies in exile; for example, 60,000 were captured after fall of France. 15,000 Polish partisans taken into custody after the Warsaw Uprising were recognized as prisoners of war and deported to POW camps. Romanian POWs held by USSR: between 100,000 to 250,000 Soviet POWs: held by Finland: 64,000; held by Germany: 5,700,000-6,200,000; held by Romania: 91,000 A small number (few dozens) were held by the Japanese following the 1939 border clashes Khalkhin Gol (at that point, however, USSR was not a participant of World War II). Yugoslav POWs: approximately half of the Yugoslav Army was captured by the Germans, resulting in about 350,000 Yugoslav POWs shortly after the German invasion of Yugoslavia; however about half of them were nearly instantly released (however, most were forced to become laborers shortly afterward). Shortly afterward, Germans released more prisoners, retaining only the Serbs (about 130,000). Due to the infighting in Yugoslavia, over 100,000 partisans opposed to the victorious, communist aligned groups were taken into custody by their opponents near the end of the war.

By country of capture: