Kalila and Dimnah is one of the common literary and cultural works of India and Iran and many of its contents were written based on the Aryan thought of these two peoples. In the present article, the issue of social stratification in the chapters “The Lion and the Bull” and “Investigation of the Conduct of Dimnah” has been analyzed with a mytho-sociological approach and with a descriptive-analytical method. The mytho-sociological analysis is a method that can reveal the mythological roots of some sociological concepts. The ideas of Georges Dumézil show that classification among Indo-European peoples was one of the main structures of creating social order. Kingsley Davis and Wilbert Moore also hold such beliefs in their sociological studies. The analysis of the aforementioned chapters of Kalila and Dimnah with these two mythological and sociological theories shows that the structure of the story of “The Lion and the Bull” is consistent with the class structure of Indo-European societies; a class structure that does not tolerate class mobility in any way and as it is clear in the “Investigation of the Conduct of Dimnah” chapter, those who engage in class mobility will have no end but destitution and destruction. In the studied chapters, Dimnah is the agent of failed class mobility, Kalila is the defender and acceptor of stratification as an undeniable reality; and the lion, lion’s mother, and the panther, who belong to the elite class, are the protectors and maintainers of stratification as a regulatory structure. The stratification in these chapters is another form of the mythical tripartite functions of Indo-European societies, which itself has become the cause of the formation of social classes in these societies.