Ehlers and Clark’s cognitive model of posttraumatic stress disorder (PTSD) highlights the importance of negative appraisals in maintaining posttraumatic stress. Recent research suggests that alienation appraisals, defined as feeling disconnected from the self and others, mediate the relationship between traumatic events and subsequent PTSD symptoms. No systematic review has been conducted which explores the relationship between alienation appraisals and PTSD symptoms in trauma-exposed adults, despite the important clinical implications posed by this relationship. A systematic search of SCOPUS, Web of Science, PsycInfo, MEDLINE, CINAHL Plus and PILOTS databases found 470 studies, 9 of which met full inclusion criteria. Studies were quality assessed for risk of bias using the QATSDD quality assessment tool. A random effects meta-analysis for the relationship between alienation appraisals and PTSD symptoms showed a total effect size of r = .57, with 95% confidence intervals between .46 and .66 (Z = 8.41, p < .001). The effect size was large, suggesting that as alienation appraisals increase, PTSD symptoms increase. Although a strong, positive relationship was found between alienation and PTSD symptoms, the mechanism of this relationship remains unclear. Limitations of the research included significant heterogeneity across studies and the fact that data is correlational. Future research to explore why alienation appraisals are significant in posttraumatic stress may further help to inform therapeutic approaches to target alienation appraisals in trauma survivors. This review recommends the clinical assessment of alienation appraisals, when exploring the impact of the traumatic experience on the survivor.