Concerns about post-traumatic stress disorder (PTSD) management among ambulance personnel are increasing, given the frequency at which they are exposed to trauma, and the associated high prevelance of PTSD. This study examines work characteristics including burnout, supervisor support, psychosocial safety climate (PSC), and their contribution to PTSD among 441 Australian ambulance personnel. Descriptive analysis, bivariate correlation and a multiple steps hierarchical binary logistic regression were performed to analyse the data. The study found that ambulance personnel experienced average level of PSC and burnout. Their supervisor support was above average levels. Prevalence of PTSD among ambulance personnel was 21.8%. Reduced personal burnout was shown to decrease the prevalence of PTSD. General support from supervisors however, was not found to reduce PTSD. Instead, PSC was shown to be more important. More research and interventions designed to promote PSC and manage burnout are recommended for PTSD management among ambulance personnel.