The aim of this article is to study the construction of the Spanish education system and its relationship with nationalist education policies. Throughout the 20th century, there has been a great deal of tension between Spanish nationalism and Basque and Catalan nationalism, in particular, over the establishment of a national curriculum that is the expression of different conceptions of national identity. In this period, the Spanish education system evolved from centralisation to decentralisation, and as a result brought about the creation of the Spanish national curriculum. The educational contributions made in Catalonia and the Basque Country were included in this process, which partially satisfied the aspirations of these communities.