From the point of view of studying the centuries-old history of the Turkish language, these language monuments created by Turkish poets and writers in the Middle Ages are important sources. The study of these monuments written in the Turkish language, and the study of their phonetic, lexical, and grammatical features also create conditions for determining the literary norms of the Turkic languages. From this point of view, the analysis of the vocabulary of “Jamshid and Khurshid”, a Turkish language written monument of the 14th-15th centuries, is both important and interesting from the point of view of studying the existence of Turkic words.In this article, the lexicon of Turkic origin has been studied in the language of Ahmadi’s masnavi “Jamshid and Khurshid”, the words of Turkic origin involved in the research have been compared with their usage forms in modern Turkic languages. As a result of the research, it has been found out that there are enough words of Turkic origin among the nouns, verbs, and numeral words used in the language of the monument. However, in the lexicon of “Jamshid and Khurshid” verbs occupy a greater place among the words of Turkic origin. In the lexicon of the 14th-15th century written monument “Jamshid and Khurshid”, carrying the linguistic features of Anatolian Oghuz Turkic, some of the words of Turkic origin have been preserved with minor phonetic changes, and some have been preserved their functionality as they are in modern Turkic languages.