’With the global energy transition towards more decentralized and sustainable systems, peer-to-peer (P2P) energy trading has emerged as a prominent energy exchange model, attracting increasing attention from both academia and industry. P2P energy trading not only facilitates the efficient utilization of distributed energy resources (DERs) but also enables autonomous energy transactions. This paper provides a comprehensive review on P2P energy trading, starting with an explanation of the P2P energy network, P2P market structures, and blockchain in P2P energy trading. The main body reviews existing research from six key research domains: trading platform, market clearing method, security, uncertainty, modeling of users behavior, and experimental validation. Subsequently, the paper discusses key factors in deployment of P2P energy trading systems. Finally, opportunities and challenges in the future are outlined, and conclusions are drawn.