Background: Exposure to parental death in childhood has been strongly associated with offspring suicide although few studies have applied theoretical models to conceptualise this relationship. Methods: Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses -Scoping Reviews guidelines, we conducted a scoping review of primary studies that identified a theory/framework explaining the aetiology of suicidal behaviour in adulthood, following childhood exposure to external-cause parental death, including suicide. Results: The search yielded 1598 articles. Following full-text screening, 23 studies were identified as meeting inclusion criteria. Data extraction was then completed and found that the studies collectively referenced nine theories. The specific theories identified covered a range of biopsychosocial frameworks and included attachment theory, familial transmission of suicide, conservation of resources framework, diathesis-stress model, social integration theory, socio-ecological model, social learning theory, critical period hypothesis or life course approach and the developmental model of antisocial behaviour. Limitations: It was beyond the scope of this review to conduct rigorous testing and evaluation of the theories identified. Future research could extend on this study by developing criteria to assess the range of theories and frameworks on suicide exposure, as well as the studies providing evidence for these theories, in order to guide more advanced theory development as well as policies, programs and interventions. Conclusions: Based on these theories, the authors proposed that using an integrated biopsychosocial model will provide a more comprehensive understanding of the diverse risk and protective factors for suicidal behaviour following parental death.