Machine Type Communication (MTC) is a key component of future communication technologies and plays a vital role in the widespread adoption of the Internet of Things (IoT). MTC connects millions of low- power devices, presenting a major challenge in efficiently managing this large volume of connections. When these devices link to MTC servers through 5G networks, they must undergo individual authentication and key agreement procedures, which can lead to significant signaling con- gestion. To tackle this problem, this paper introduces a group-based authentication and key agreement protocol that greatly reduces signaling congestion in LTE-A networks. The security of the proposed protocol has been validated using the Automated Validation of Internet Security Protocols and Applications (AVISPA) tool. It ensures mutual authentication, key agreement, and robust defense against various security threats, including replay attack, man-in-the-middle attack and impersonation attacks, thereby improving both the efficiency and security of MTC in 5G networks.