This thesis comprising three individual studies, examined the relationship between maltreatment, emotion-related parenting behaviours and executive function in a sample of maltreated and non-maltreated preschool children. Children (N = 107; ages 4-5) and caregivers were recruited from three cohorts: foster care agencies (serious maltreatment); child protection early intervention programs (low to moderate maltreatment); and community preschools (no maltreatment). Executive function was assessed using performance-based measures (Happy–Sad Stroop Task, Tapping Test and Dimensional Change Card Sort) and a caregiver rating scale (Behaviour Rating Inventory of Executive Function). Parenting was assessed with a self-report measure (Coping with Children’s Negative Emotions Scale) and maltreatment types were coded based on files and reports. Study 1 demonstrated that the profile of BRIEF-P scores for maltreated children was more elevated (indicative of worse executive function) relative to the non-maltreated group. Caregiver ratings were weakly correlated with performance-based executive function measures and maltreatment risk had a partial moderating effect on this association. Study 2 provided evidence that maltreatment risk uniquely predicted executive function, independent of parental depression and child ethnicity. Specifically, supportive parental reactions (emotion focused, expressive encouragement) buffered harmful effects of maltreatment on executive function, while unsupportive reactions (punitive, minimising) amplified the risk. Study 3 provided preliminary support for the common adverse effects of maltreatment on both pre-schoolers’ emotion and cognitive regulation. Findings highlighted that early maltreatment negatively impacts the development of executive function in preschool-aged children. Potential avenues for improving cognitive outcomes in maltreated young children include early assessment of executive function, evidenced-based parenting programs and early education programs
