In the article, the extent, the types and the functions of the “determinative groups”, one of the word groups in the Turkish language, are identified and the systematics of the determinative groups is analysed in terms of syntax. In addition, by considering the examples of the determinative groups selected from various literary works written in the period called Old Turkic, the structures, the types and the functions of the determinative groups in Old Turkic are expounded in detail in comparison with the system of the determinative groups in the Turkey Turkish. According to the results gained in the research, an approach is established with an alternative view to the system of the Turkish determinative groups and also the determinative groups used in the Old Turkic are analysed from the point of constructional syntax.