With the pervasive use of communications technologies, security of multiparty communication systems becomes crucial more than ever. However, providing a secure communication in distributed and dynamic networks is a challenging issue. Dynamic group key agreement protocols are one of the best candidates to overcome this issue. In dynamic group key agreement protocols, each participant in a group involves into the key computation. Moreover, dynamic group key agreement protocols provide auxiliary dynamic group operations for updating the group key when the set of participants is updated. In this paper, a comparative study on the scalability of dynamic group key agreement protocols is presented to show the best possible group key agreement protocol for specificsized networks. Furthermore, we present simulations for scalability analysis of dynamic group key agreement protocols. Finally, we analyze and compare the performance of protocols regarding computational and communications costs.