The current study aimed to test a key theoretical prediction of rational emotive behavior therapy (REBT) theory by assessing the role of general and trauma-specific irrational beliefs in the prediction of posttraumatic stress responses. A sample (N = 313) of trauma-exposed emergency service workers participated in the study. Structural equation modeling results demonstrated that an REBT-based model provided satisfactory model fit and explained 89% of variance in posttraumatic stress symptomatology. Theoretical predictions were supported, with results demonstrating that general-level irrationality indirectly impacted posttraumatic stress responses via a set of trauma-specific irrational beliefs. Results indicate the importance of irrational beliefs in predicting posttraumatic stress responses.