The pogroms have been widely debated in the historiography, including the extent to which Ukrainian nationalists played a central or complicit role.

[5] On 28 September 1939, after the joint Soviet-German invasion, the USSR and Germany signed the German–Soviet Frontier Treaty, which assigned about 200,000 km2 (77,000 sq mi) of Polish territory inhabited by 13.5 million people of all nationalities to the Soviet Union.

[9] According to scholar Jeffrey Kopstein, the Polish population "awaited the German arrival with a mixture of fear and hope", having resented their loss of control of the city under Soviet occupation.

[12] Nonetheless, the local OUN-B's preparations for the anticipated German invasion included May 1941 instructions for ethnic cleansing to its planned militia units: “At a time of chaos and confusion it is permissible to liquidate undesirable Polish, Russian, and Jewish activists, especially supporters".

[16] Lviv was occupied by the Wehrmacht in the early hours of 30 June 1941; German forces consisted of the 1st Mountain Division and the Abwehr-subordinated Nachtigall Battalion staffed by ethnic Ukrainians.

That day, Jews were press-ganged by the Germans to remove bodies of NKVD's victims from the prisons and to perform other tasks, such as clearing bomb damage and cleaning buildings.

During the afternoon of the same day, the German military reported that the Lviv population was taking out its anger about the prison murders "on the Jews ... who had always collaborated with the Bolsheviks".

The OUN encouraged violence against Jews, which began in the afternoon of 30 June, with active participation from the Ukrainian militia who could be identified by armbands in national colours: yellow and blue.

[25] At least two members of the OUN-B, Ivan Kovalyshyn and Mykhaylo Pecharsʹkyy, have been identified by the historian John Paul Himka from photographs of the pogrom.

[27] More recently, Ksenya Kiebuzinski and Alexander Motyl have emphasised the range of contributory factors, including: the visibility of Jewish activists in Communist ranks (despite the fact that a minority of Jews supported the Soviet occupation), fuelling a widespread perception from Polish and Ukrainian residents that Jews supported Communism and the Soviet Union, a perception shaped by prevalent antisemitism among Ukrainian and Polish communities, who had little meaningful interaction with Jewish neighbours and refugees.

They tried to recruit locals, but adherence was spotty and opportunistic... excessive focus on their role risks overlooking an essential feature...: the participation of broad segments of the Ukrainian population in the pogrom's mass, carnivalesque character."

[32] The Ukrainian militia received assistance from the organisational structures of OUN, unorganized ethnic nationalists, as well as from ordinary crowds and underage youth.

[39] German propaganda passed off all victims of the NKVD killings in Lviv as Ukrainians, although about one-third of the names on the Soviet prisoner lists were distinctly Polish or Jewish.

[40] Over the next two years both German and pro-Nazi Ukrainian press—including Ukrains'ki shchodenni visti and Krakivs'ki visti—went on to describe horrific acts of chekist (Soviet secret police) torture, real or imagined.

These hopes had been fueled by the circle around Alfred Rosenberg, who was subsequently appointed as head of the Reich Ministry for the Occupied Eastern Territories and within Abwehr.

Hitler, however, was adamantly opposed to Ukrainian statehood, having set his sights on the ruthless economic exploitation of the newly acquired colonial territories.

Survivors observed Ukrainians in Wehrmacht uniforms participating in the pogroms, but it remains unclear what role the battalion played.

[42] The Lwów Ghetto was established in November 1941 on the orders of SS-Brigadeführer Fritz Katzmann, the SS and Police Leader (SSPF) of Lemberg.

Following the 1941 pogroms and Einsatzgruppe killings, harsh conditions in the ghetto and deportations to Belzec and the Janowska concentration camp had resulted in the almost complete annihilation of the Jewish population.

Other historians, such as Alexander J. Motyl, have criticised Himka's position as one-sided, and emphasised the complexity of the events, including Polish participation.

In October 1943, OUN issued instructions for preparation of materials that would suggest that Germans and Poles bore responsibility for anti-Jewish violence.

[47][48] According to Rudling, the "whitewashing" continued after the war, with OUN's propaganda describing its legacy as a "heroic Ukrainian resistance against the Nazis and the Communists".

OUN closely guarded its archives, limiting access to information and retyping, back-dating, and censoring its documents before releasing them to scholars.

[52] In post-Soviet Ukraine, the new commemorative practices focused primarily on Lviv's Ukrainian past, while the lost Jewish and Polish populations were largely ignored.

[53] In 2008, the Security Service of Ukraine (SBU) released documents which it stated indicated that the OUN may have been involved to a lesser degree than originally thought.

According to scholars John-Paul Himka, Per Anders Rudling, and Marco Carynnyk, this collection of documents, titled "For the Beginning: Book of Facts" (Do pochatku knyha faktiv), was an attempt at manipulating and falsifying of World War II history.

According to Himka, all that this document proved was that OUN wanted to dissociate itself from anti-Jewish violence to aid in its goals of establishing a relationship with the West.

[54][55][56] More recently, Ksenya Kiebuzinski and Alexander Motyl have criticised historians such as Himka who place too much explanatory emphasis on Ukrainian nationalists.

4) As Timothy Snyder argues, similar forms of violence occurred in areas (such as Eastern Ukraine) where the OUN had no influence.