This study examines social problem-solving skills following childhood traumatic brain injury (TBI) and its association with self-regulation, and social and behavioural functioning. Participants included 65 children with moderate to severe TBI and 65 children without TBI, all between 6 and II years of age. Social problem-solving, self-regulation, and social and behavioural functioning were assessed 2-5 years following injury. Children were administered a newly developed semi-structured task to assess their solutions to hypothetical situations involving social problems or dilemmas. When compared with uninjured children, those with TBI suggested avoidant and aggressive solutions more often and assertive solutions less often in response to the hypothetical situations. Children's self-regulatory skills, as measured by the Matching Familiar Figures Test (MFFT), Test of Everyday Attention for Children (TEA-Ch) and the Delay of Gratification Task (DGT), collectively accounted for significant variance in their solutions to social problems, such that better self-regulation predicted more assertive solutions and fewer aggressive solutions. Assertive solutions were positively related to parent- and teacher-rated social and behavioural outcomes, whereas aggressive solutions were negatively related to the outcomes. The difficulties in social problem-solving skills demonstrated by children with TBI may help account for their poor social and behavioural functioning.