In the past decade, there has been an increased focus on the role of physiology in interpersonal interactions, resulting in a surge of research exploring topics related to communication in close relationships. This growing line of research has explored topics such as affectionate communication, forgiveness, communication apprehension, and social support. Contributing to the increase in physiological research on communication processes is a greater recognition of the bidirectional nature of the associations among communication and the body. Researchers studied both the physiological outcomes of communication episodes (e.g., stress responses to conflict conversations) and the effects of physiology on the communication process (e.g., the influence of hormones on postsex communication). The Oxford Handbook of the Physiology of Interpersonal Communication offers a comprehensive review of the most prolific areas of research investigating both the physiological outcomes of interpersonal communication and the effects of physiology on interpersonal interactions. This edited volume serves as a resource for both researchers and students interested in investigating the mutual influence of physiology and communication in close relationships.