ENThe article presents the political, social and legal aspects of relations between the Polish state and national minorities in the period 1918–1928. The Second Polish Republic had a high level (over 30%) of national minorities – polish political thought created models from assimilation of minorities to coexistence – federation and state assimilation. International commitments forced the government to adopt democratic solutions despite nationalist trends. Sharp protests against the minority were caused by the school language law (with the model of a bilingual school), which in the opinion of the minority was aimed at assimilation of national minorities.