The present study aims to examine which maladaptive and Big Five personality traits, as well as which lower order facets, are related to symptoms specific to PTSD (i.e., intrusions and avoidance). Unique effects were isolated by controlling for nonspecific general depression that occurs in the disorder but is not specific to it. 707 undergraduate students were administered a self-report online survey to assess their personality, trauma history, PTSD and mood symptoms. Additionally, data from 536 9/11 World Trade Center (WTC) responders who have been administered personality, PTSD, and mood surveys as part of a longitudinal study were analyzed. As expected, neuroticism was highly correlated with PTSD, but had fewer associations with PTSD dimensions after controlling for depression. Trust and agreeableness emerged as important, being negatively related to PTSD, while most maladaptive personality domains and facets were positively related to PTSD (perceptual dysregulation had the highest association). Other traits, such as antagonism and openness, were not significantly related to PTSD. There is growing evidence that clinical interventions can change personality traits; the present study provides new personality targets for intervention that are uniquely related to PTSD