Following the September 1939 Ribbentrop-Molotov Pact and German-Soviet Occupation of Poland, many Jewish refugees from central and western Poland settled in Olyka in the fall of 1939, as did 60 Jewish refugees from Czechoslovakia. Jewish organizations and institutions were forced to disband. After the German invasion of Ukraine in June 1941, as part of Operation Barbarossa, the German 6th Army entered Olyka, destroyed houses, killed 100 Jews, and kept the remaining Jews in an open ghetto. Around 150 Jews evacuated eastward; most Jews stayed in the ghetto. Jews and non-Jewish Ukrainians continued to trade goods and food in and around the ghetto; for example, an Olyka ghetto Jew traded his house for sixteen kilograms of rye due to famine. As part of the Einsatzgruppen action of August 1941, 720 Jews, including Rabbi Alter Yosef Dovid Landa, were killed at the Olyka Castle and at the town's Jewish cemetery towards .