Seals and clay sealings are the most valuable evidence for studying the economic, political and cultural structures of the different past societies. Due to the lack of resources to explain the various characteristics of Seleucid and Parthian material culture, studying the seals of these periods can reveal not only the artistic sides of glyptic material but to clarify the roles played by sealings in the social and economic contexts of the Seleucid and Parthian societies. Seven seals which are currently being preserved in the Semnan Museum are described and studied in the present paper. These seals have been discovered through illegal excavations. Their patterns and styles are usually influenced by Greek art elements, including animal motifs, the Greek goddess Athena and human illustrations in the majority, which is probably because of the greater attention to human and humanist perspectives among the Greek artists. The present study aims at analysing the motifs of the seals, as well as making comparisons to identify similarities with other cases found in different sites such as Tel Kedesh (Israel), Nisa (Turkmenistan) and Dura-Europos (Syria) in order to suggest a more precise dating for the mentioned seals.