Purpose This article investigated relationship and social network change in the presence of a social cognition impairment post right hemisphere (RH) stroke. Impaired emotion perception and inferential reasoning are sources of interpersonal difficulty in people with social cognition impairment after traumatic brain injury. People with an RH stroke have also been identified as vulnerable to interpersonal relationship change. However, the influence of impairments in particular domains of communication or cognition on relationship and social network maintenance is yet to be explored. Method A multiple-case study methodology allowed for testing of theoretically developed propositions by exploring social networks and relationships within and between seven participant-proxy dyads. Purposeful recruitment was based on first-onset RH stroke and impaired social cognition, as determined by The Awareness of Social Inference Test. Results Social network size reduction (71.4%, n = 5) and interpersonal relationship change (85.7%, n = 6) were attributed to altered communication style, impairments in social cognition, and reduced insight and/or motivation. The spouse emerged as a facilitator of social engagement. Conclusion This study contributes to our understanding of the challenges experienced by people with impaired social cognition post RH stroke in maintaining relationships and their social networks.