ENThe Second Polish Republic had been a multinational and multiethnic state, situation which was a challenge both for the central authorities and the administration at the regional level. This article is a review of the interwar and post-war literature dealing with the issue of Polish–Lithuanian relations in the interwar period. In order to show the att itude of the Lithuanian population in the pre-war Vilnius and Bialystok Voivodeships before the outbreak of World War II and the position of ethnic Lithuanians to emerging war and the Polish population, it was necessary to analyze Polish and Lithuanian source materials. Key words: Second Polish Republic, Lithuanian minority, Polish–Lithuanian relations, Vilnius Voivodeship, Bialystok Voivodeship.