The prevalence of burnout among university students is increasing with consequences for their academic performance. Attachment theory, as a theory of affect regulation and interpersonal relationships, may be an important framework that helps to explain why some students experience academic burnout while others do not. This study aims to examine the links between attachment orientations and levels of academic burnout and to explore the mediating role of emotion regulation strategies in this relationship. This cross-sectional study included 205 students from different Portuguese universities. Multiple mediation models conducted in PROCESS showed that both attachment anxiety and attachment avoidance were associated with higher levels of personal and academic-related burnout. Additionally, rumination and suppression mediated the association between attachment anxiety and burnout while putting into perspective and suppression mediated the association between attachment avoidance and burnout. Results are discussed in the light of attachment theory and clinical implications are provided to prevent academic-related burnout.