Early-life adversity is associated with the development of internalizing and externalizing problems in children. Despite this, there is a need to understand the mechanisms linking these experiences to psychopathology, especially in clinical samples. This cross-sectional study tested emotion dysregulation as a mechanism linking early-life threat to psychopathology in a clinical sample of children with disruptive behavior problems. We also explored parental positive reinforcement as a protective factor in these pathways.A clinical sample of 606 children aged 6-12years, referred to a mental healthcare hospital, were included. Parent-reported child threat, and parent- and teacher-reported child emotion dysregulation and psychopathology, were collected. Path analysis was used to explore the mediating effect of emotion dysregulation in the relation between threat and psychopathology. The moderating effects of parental positive reinforcement were explored through moderated-mediation analyses. Emotion dysregulation partially mediated the association between threat and both internalizing (β = .18, P = .006)and externalizing (β = .19, P = .002) problems. Positive reinforcement did not buffer the association between threat and emotion dysregulation (β = .09, P = .62) or the association between emotion dysregulation and internalizing (β = -.003, P = .20)or externalizing (β = -.002, P = .35). Poor emotion regulation may be a transdiagnostic mechanism linking early-threat with internalizing and externalizing problems in clinic-referred children with disruptive behaviors. Factors aside from parental positive reinforcement should be explored as protective factors in these pathways, including those directly implicated in the purported mechanisms linking these factors over time.