Childhood trauma can result in developmental and psychosocial problems leaving teachers struggling to manage the effects of students' trauma and potentially leading to increased burnout. The present study investigated whether teachers' attitudes towards teaching trauma-affected students and prior experience with trauma predicted teacher burnout. Five types of prior experience were informed by the multidimensional model of attitude strength: the extent and valence (i.e., how favourable or unfavourable the experience was) of direct teaching experience, the extent and valence of personal experience, and the extent of indirect experience (trauma-training). The study investigated whether the relationships between prior experiences and burnout were mediated by teachers' attitudes, controlling for teacher age. Australian mainstream teachers (N = 536) were recruited to an online survey through snowball sampling on social media. Results showed that attitudes significantly mediated the relationships between all experience variables with burnout, except for the extent of personal experience. More favourable attitudes were predicted by more direct experience (contrary to the hypothesised direction) and indirect experience (as hypothesised). Regarding valence of experience, exploratory analyses found more favourable direct and personal experiences predicted more favourable attitudes. Supporting the hypotheses, all mediations found more favourable attitudes predicted less burnout, while more personal experience predicted greater burnout. These cross-sectional findings suggest that greater experience teaching trauma-affected students, trauma-training, and fostering favourable perceptions of teachers' personal trauma may protect teachers from burnout. Future research using longitudinal designs is needed to support causal effects between teachers' experiences, attitudes, and burnout.