The current study investigated the predictions of rational emotive behaviour therapy's (REBT) model of psychological health that rational beliefs would act as cognitive protective factors against posttraumatic stress responses. The study aimed to contribute original data regarding the role of functional cognitions in the prevention of posttraumatic stress symptomology. A model consistent with REBT's theory of psychological health was investigated through the use of structural equation modelling among a sample of 309 international emergency service personnel who had all been exposed to a significant life trauma. Results indicated that the REBT model of posttraumatic stress responses was found to be an acceptable fit of the data (chi(2) = 199.99, df = 94, p < .001; RMSEA = .06 (CI 90 % = .05/.08); SRMR = .05; CFI = .93; TLI = .91) and explained 76 % of variance in posttraumatic stress symptoms. Self-acceptance beliefs and high frustration tolerance beliefs negatively predicted posttraumatic stress responses; non-catastrophizing beliefs positively predicted posttraumatic stress responses; and indirect effects were observed between preference beliefs and posttraumatic stress responses via self-acceptance and high frustration tolerance beliefs. Results suggest that rational beliefs are negatively associated with posttraumatic stress responses and support the REBT model of psychological health. Current results contribute important information regarding the role of functional cognitions in the alleviation of posttraumatic stress symptoms.