Post‐traumatic stress disorder (PTSD) is a common reaction to traumatic experiences. We propose a socio‐interpersonal model of PTSD that complements existing models of post‐traumatic memory processes or neurobiological changes. The model adds an interpersonal perspective to explain responses to traumatic stress. The framework draws from lifespan psychology, cultural psychology and research into close relationships and groups. Additionally, clinical knowledge about PTSD is incorporated. This involves knowledge about shame, guilt, estrangement feelings and protective factors, such as social support and forgiveness. Three levels are proposed at which relevant interpersonal processes can be situated and should be adequately researched. First, the individual level comprises social affective states, such as shame, guilt, anger and feelings of revenge. Second, at the close relationship level, social support, negative exchange (ostracism and blaming the victim), disclosure and empathy are proposed as dyadic processes relevant to PTSD research and treatment. Third, the distant social level represents culture and society, in which the collectivistic nature of trauma, perceived injustice, and social acknowledgement are concepts that predict the response trajectories to traumatic stress. Research by the current authors and others is cited in an effort to promote future investigation based on the current model. Methodological implications, such as multi‐level data analyses, and clinical implications, such as the need for couple, community or larger‐level societal interventions, are both outlined. Copyright © 2012 John Wiley & Sons, Ltd.Key Practitioner Message The socio‐interpersonal model proposes an interpersonal view of the processes that occur in the aftermath of a traumatic experience.At the individual level, the model integrates the social affective phenomena that clinical research identifies in PTSD patients, including shame, guilt, anger, revenge and the urges or reluctance to disclose.At the level of close relationships, there is an emphasis on the role of the individuals' partner, family or social support in the development or maintenance of PTSD and its recovery.At the distant social level, societal and cultural factors, e.g., individualistic versus collectivistic or other human value orientations, are acknowledged as contributing to the severity and course of PTSD.Increasing attention should be given to new approaches of PTSD treatment that refer to an interpersonal view of PTSD, e.g., communication training, PTSD‐specific couples' therapy or community programs.