The aim of this study is to provide a linguistic comparative description of the WITCH and BABA YAGA concepts’ structures in Russian and English folk tales based on thesaurus lexeme description and content analysis. The research novelty lies in presenting lexicographic thesaurus models of the WITCH and BABA YAGA concepts in the genre of folk and fairy tales, providing a description of the semantic and semiotic structure of the given models and comparing the concepts in the two folk traditions. Research results show that the thesaurus lexeme distribution of the WITCH concepts in English and Russian texts is similar in its basic elements, while the differences between the conceptual structures manifest themselves in a variety of lexical expressions based on peculiarities of cultural interpretations. Having a lot in common with the other WITCH concepts in both traditions, the BABA YAGA concept still stands out as a unique incarnation of pagan and Christian mentality of Russian people.