Mobile Edge Computing (MEC) has emerged as a promising solution to meet the growing demand for low-latency and high-bandwidth applications and services. However, MEC nodes are often limited by computing resources, storage capacity, and energy resources, which makes them vulnerable to malicious attacks. This Special Issue aims to gather original and high-quality research papers that present recent advances and innovative solutions in the security and defense of MEC. Research areas may include (but are not limited to) network and cyberspace security, artificial intelligence, machine learning, DDoS attacks, malware, and privacy breaches. Submitted manuscripts should not have been published previously.