From the definition of Anthony D. Smith of nationalism as the process of formation of nations, the article reviews the main theories that explain the construction of the nation, grouping them into five namely groups: the modernists who understand the nation as a data, the modernist constructivist; the perennialists who conceive the nation as a data and those who argue that there is a historical permanence of the nation as a construction. Finally, there is a mention of the topics raised by postmodern writers, because they do not want to build a general theory of nationalism.