This paper seeks to contribute to the sociology of nations, a literature that is only starting to carve out its place in the social sciences. The paper offers a reconceptualization of “nations” as “national cultures”, employing an evolutionary perspective and a systemic framework in which “nations” are understood as cultural systems of a special kind. National cultures are intimately tied to natural languages, and the acquisition of a national culture occurs as part and parcel of the acquisition of a natural language. Acquiring a natural language is a prerequisite for learning other cultural systems (artefactual languages as well as other natural languages). National cultures function as metacultures. They are also the reference cultures for modern states and their citizens, a political dimension of nations that is of paramount importance, though it will only be touched on in this paper. National cultures should be considered as the most fundamental type of cultural system today.