The incident of the Twenty Classes (Turkish: Yirmi Kur'a Nafıa Askerleri, literally: "Soldiers for Public works by drawing of twenty lots", or Yirmi Kur'a İhtiyatlar Olayı, literally: "Incident of the Reserve soldiers by drawing of twenty lots") was a conscription used by the Turkish government during World War II to conscript the male non-Turkish minority population mainly consisting of Armenians, Greeks and Jews. All of the twenty classes were drawn from male minority populations and included the elderly and mentally ill. They were given no weapons and quite often they did not even wear military uniforms. These non-Muslims were gathered in labour battalions in which no Turks were enlisted. They were allegedly forced to work under very bad conditions. The prevailing and widespread point of view on the matter was that, anticipating entry to World War II, Turkey gathered in advance all unreliable non-Turkish men regarded as a potential "fifth column".
One of the main intentions of the Turkish government was to seize the assets of the minority population. The conscripted minorities were bankrupted since they could not manage their businesses during the incident of the Twenty Classes and as a result they had to sell their companies and assets for nearly nothing. After this, there followed two major events with almost the same intentions: Varlık Vergisi and Istanbul Pogrom.