The lexicographic activities of Antonio de Nebrija (1444?–1522) are present in his numerous works and their adaptations. They are different realisations of various kinds that more often than not exist in the form of a dictionary; the present study, however, deals primarily with nontechnical compilations of the lexicon. It first studies Nebrija’s sources and then the process by which the progressive amplification of lemmata took place, the modification of the criteria in the presentation of the entries, the evolution of his lexicographic concepts, and the like. In order to reach these goals the present paper analyzes, chronologically, the sources, the disposition and treatment of the entries in the vocabulary which accompanies his Latin grammar of 1481 as well as those found in the Latin-Spanish dictionaries of 1492 and 1512.