Teacher burnout is an important phenomenon that affects the education system and society as a whole. Assessment represents a form of stress for teachers, and this study explores the association between teachers' assessment-related beliefs and their burnout level. To this end, the Teachers' Conceptions of Assessment (TCoA) inventory along with the Maslach Burnout Inventory were administered to a sample of Iranian teachers of English language. Multiple correspondence analysis and multiple regression analysis were employed for data analysis. The results reveal a significant relationship between TCoA and the three dimensions of burnout (emotional exhaustion, depersonalisation and reduced personal accomplishment). It is similarly found that conceiving of assessment as irrelevant to the life and work of teachers and learners is the best predictor of Depersonalisation and Personal Accomplishment, whereas Student Accountability is the best predictor of Emotional Exhaustion. Finally, the results are discussed and implications are provided in the context of education.