Ukrainian collaboration with Nazi Germany took place during the occupation of Poland and the Ukrainian SSR, USSR, by Nazi Germany during the Second World War.

By September 1941, the German-occupied territory of Ukraine was divided between two new German administrative units, the District of Galicia of the Nazi General Government and the Reichskommissariat Ukraine. Some Ukrainians chose to resist and fight the German occupation forces and joined either the Red Army or the irregular partisan units conducting guerrilla warfare against the Germans. Some Ukrainians worked with or for the Nazis against the Allied forces. Ukrainian nationalists hoped that enthusiastic collaboration would enable them to re-establish an independent state. Many were involved in a series of war crimes and crimes against humanity, including the Holocaust in Ukraine, and the massacres of Poles in Volhynia and Eastern Galicia.

Russians, including Belarusians, Tatars and other ethnicities, who collaborated with Nazi Germany did so in various ways including participating in local administrations, in the German-supervised auxiliary police, Schutzmannschaft, in the German military, or as guards in the concentration camps.

Ukrainians were viewed as untermenschen by the Nazis due to being Slavic and were slated for extermination and enslavement in Generalplan Ost, but in practice, manpower issues on the Eastern Front required Nazi Germany to use locals for various tasks. While Hitler surmised that a small number of Ukrainians were descendants of ethnic Germans who settled in the region, Ukrainians were generally never deemed non-Slavic like other Slavs in Nazi Germany's racial hierarchy, such as Bulgarians and Croatians. Most of the Ukrainian nationalist leaders who collaborated with Nazi Germany were used for antisemitic and anti-Polish action, but were later arrested for their pro-Ukrainian views.

Stalin, the ruler of the USSR, and Hitler, the ruler of Nazi Germany, both demanded territory from their immediate neighbour, the Second Polish Republic. The Soviet invasion of Poland in 1939 brought together Ukrainians of the USSR and Ukrainians of what was then Eastern Poland (Kresy), under a single Soviet banner. In the territories of Poland invaded by Nazi Germany, the size of the Ukrainian minority became negligible and was gathered mostly around UCC (УЦК [uk]), formed in Kraków.

Less than two years later, Nazi Germany attacked the Soviet Union. The German Operation Barbarossa began on June 22, 1941. Operation Barbarossa brought together native Ukrainians of the USSR and the prewar territories of Poland annexed by the Soviet Union. By September the occupied territory was divided between two new German administrative units: to the southwest, the District of Galicia of the Nazi General Government, and the northeast, Reichskommissariat Ukraine, which stretched all the way to Donbas by 1943.

Reinhard Heydrich noted in a report dated July 9, 1941 "a fundamental difference between the former Polish and Russian [Soviet] territories. In the former Polish region, the Soviet regime was seen as enemy rule... Hence the German troops were greeted by the Polish as well as the White Ruthenian population [meaning Ukrainian and Belarusian] for the most part, at least, as liberators or with friendly neutrality... The situation in the current occupied White Ruthenian areas of the [pre-1939] USSR has a completely different basis."

Ukrainian nationalist partisan leader Taras Bulba-Borovets gathered a force of 3,000 in summer 1941 to help the Wehrmacht fight the Red Army. In September 1942, Borovets entered into negotiations with the Soviet partisans of Dmitry Medvedev. They tried to attract him to the struggle against the Germans but could not reach an agreement. Borovets refused to obey the Soviet command structure and feared German retaliation against Ukrainian civilians. Still, until the spring of 1943 neutrality was maintained between the Borovets detachments and the Soviet partisans. Parallel to the negotiations with the Soviets, Borovets continued to try to reach an agreement with the Germans. In November 1942, he met with Obersturmbannführer Puts, the head of the security service of Volhynia and Podolia general district.