War veterans experience significant social isolation due to problems in their cognitive-emotional process. Therefore, the present study aimed to determine the mediating role of sensitivity to rejection in the relationship between emotional inhibition and social isolation in veterans with post-traumatic stress disorder (PTSD). In this descriptive and correlational research, 300 veterans with PTSD, admitted and treated at Isar Psychiatric Hospital in Ardabil, Iran, in 2022, were selected as a targeted sample and investigated throughout the process. The study made use of Russell’s Social Isolation Scale (1996), Kellner’s Emotional Inhibition Questionnaire (1986), and Berenson et al.’s (2009) Rejection Sensitivity Questionnaire for data collection. They were then analysed utilising Structural Equation Modeling (SEM) using SPSS and Lisrel 8.8 software. The results confirmed the causal relationship between emotional suppression, rejection sensitivity, and social isolation in veterans with PTSD based on various fit indices. Inhibition of emotion and sensitivity to rejection directly affected the social isolation of veterans with PTSD. Moreover, emotional inhibition through sensitivity to rejection indirectly affected the social isolation of veterans with PTSD (P<0.05). Therefore, emotional inhibition and sensitivity to rejection play a vital role in the social isolation of PTSD patients. In addition, targeting these two components through psychological treatments can effectively reduce the social isolation of veterans with PTSD.