The present work introduces to the annotated re-edition of an article written by the prominent Ossetian scientist, folklorist and teacher Grigory Alekseevich Dzagurov (1888–1979), which was published in 1924 under the title “The Japhetic Theory of Academician N. Ya. Marr and the Question of the Origin of the Ossetians”. The text, reproduced in a new annotated version with identification of the sources used by the author, introduces to the new linguistic theory promoted by Academician N. Ya. Marr (1864–1934), postulating the relationship between Hamito-Semitic and Kartvelian languages as well as the idea of linguistic mixing and crossing. By deliberately overusing direct quotations from the works of the creator of Japhetic linguistics, Dzagurov gives a brief overview of the main provisions of Marr’s linguistic theory, showing its direct relation to the question of the dual nature, Indo-European (Iranian) and Japhetic, of Ossetic. At that time, as is well known, linguistic arguments were readily provided when discussing thorny questions about the ethnogenesis of peoples. Overall, Dzagurov’s article has historical significance in many respects. Firstly, it testifies to the reception of the Japhetic stage of Marr’s linguistic theory (that is, before the emergence of the New Doctrine of Language) with respect to the study of the Iranian linguistic world in the Northern Caucasus. Secondly, such ideas about the phenomena of the Caucasian substrate and language mixing were skillfully developed over the following decades by one of the best students of Marr, V. A. Abaev (1900–2001), who identified numerous Caucasian elements in the Ossetian language at all language levels. Finally, it is interesting to notice that it was Dzagurov who gave a recommendation on Abaev’s application for admission to the Petrograd State University, thus indirectly contributing to the onset of an important stage in the history of Ossetian studies and, in general, Soviet linguistics.