Impairments in social performance are common consequences of TBI, yet the neuropsychological basis of these impairments is not well understood. This is particularly true for adolescents, who have the highest incidence of TBI and are at a critical stage of developing social and relationship skills. To address this, adolescents with TBI were compared to their typically developing peers on a social cognition task that included Theory of Mind (ToM) questions. As ToM may be necessary for the development of culture-specific social knowledge, the two groups also were compared in regard to their social beliefs. There were significant differences between injured and uninjured adolescents in social cognition, with group differences increasing as a function of the requirement for ToM. There were few differences in self-reported social knowledge and social beliefs. The implication of this discrepancy for the rehabilitation of adolescents with TBI is discussed.