This study aimed to investigate factors associated with persistent Post-Traumatic Stress Disorder (PTSD) in people with Spinal Cord Injury (SCI). In the context of a cognitive model, it sought to determine how influential cognitive appraisals were in predicting persistent PTSD when compared to other known predictor variables in the literature such as injury severity. A sample of 50 inpatients receiving rehabilitation for SCI who were 3–24 months post-injury were interviewed using a series of standardized measures of PTSD symptoms and diagnosis, post-traumatic cognitive appraisals, social support, and injury severity. For PTSD symptoms, significant relationships were found for greater injury severity, lower satisfaction with social support and more negative cognitions. Negative cognitions were found to predict variance in PTSD symptoms over and above the non-cognitive variables, although gender and injury severity were also predictors. The only significant predictor of PTSD diagnosis was the cognitive sub-scale “negative cognitions about the self”. Cognitive appraisals were found to be important predictors of persisting PTSD in an SCI population. This supports the cognitive model of PTSD and the development of cognitive therapies for PTSD in this population.