The research subject of this article is Dmowski’s concept of the nation, which constitutes the core of his vision of socio-political reality. The research objective of the article is to seek answers to the following questions: how Dmowski defined the nation and whether his views in this respect evolved? Which nation-building factors can be distinguished when analysing his understanding of the nation and which of them accounted for the essence of the nation? Also, whether political conditions influenced his definition of the nation? The analysis of the concept of nation was presented by referring to the nation-forming factors. Dmowski oscillated between various determinants, mainly pointing to morality, instincts and the spirit of the nation. The lack of precision in defining the nation was the result of his political pragmatism, as it provided an opportunity to adapt this overarching concept to political needs. The answers to the research questions posed here complement the rich scholarly discourse on Dmowski, as well as research on nationalisms.