The Gudovac massacre was the mass killing of around 190 Bjelovar Serbs by the Croatian nationalist Ustaše movement on 28 April 1941, during World War II. The massacre occurred shortly after the German-led Axis invasion of Yugoslavia and the establishment of the Ustaše-led Axis puppet state known as the Independent State of Croatia (NDH). It was the first act of mass murder committed by the Ustaše upon coming to power, and presaged a wider Ustaše-perpetrated campaign of genocide against Serbs in the NDH that lasted until the end of the war.

The Genocide of Serbs in the Independent State of Croatia was the systematic persecution of Serbs committed during World War II by the fascist Ustaše regime in the Nazi German puppet state known as the Independent State of Croatia between 1941 and 1945. It was carried out through executions in death camps, as well as through mass murder, ethnic cleansing, deportations, forced conversions, and war rape. This genocide was simultaneously carried out with the Holocaust in the NDH as well as the genocide of Roma, by combining Nazi racial policies with the ultimate goal of creating an ethnically pure Greater Croatia.