Job burnout is a major predicament globally, especially among the helping professions. Based on the job demands–resources (JDR) theory and on attachment theory, this study explored the relations between a history of childhood maltreatment (CM), insecure attachment styles (avoidant and anxious), perceived supervisor support and job burnout. A sample of 320 helping professionals participated in the study, of which 35% reported experiencing CM. Findings confirmed the hypothesis that a history of CM was positively related to both avoidant and anxious attachment styles. Anxious attachment style partly mediated the relationship between CM and burnout. In addition, the relationship between CM and burnout was mediated by avoidant attachment style and perceived supervisor support, so that highly avoidant professionals perceived their supervisors as less supportive, reporting higher levels of burnout. Notably, there were no discernible variations in burnout levels when comparing professionals who had experienced maltreatment with those who had not. The study highlights the value of adopting an attachment perspective to better understand job burnout among the helping professions.