Works of Caucasian historians in the ancient times contain evidence of Caucasian societies’ division. Although these works have emphasized on the aristocratic structure of the Caucasian societies, they also include evidence of the life of the lower classes in ancient times. The present article has invoked the works of Armenian and Georgian historians like Moses Khorenasi, Pavstos Buzand, Lazar Parapets, Leonti Mrovli and Moses Dasxurantsi. Yet, in order to compare the Caucasian social structures with the corresponding Sassanid and Parthians structures, and to give a clearer picture of the ancient Caucasian society, it has also tried to benefit from a simultaneous study of Roman and Middle Persian sources. The final findings of the research prove that the social structure of Caucasus in the Parthian and Sassanid periods is similar to the tripartite social structure of Iran in the same periods - The structure that consists of rulers, warriors and peasants.