This exploratory investigation sought both to gain a better understanding of the mental representations of attachment in high-risk, maltreated adolescents and to explain how, if at all, unresolved attachment representations are related to behavioural maladjustment. Parent ratings, self-report ratings and attachment state of mind were obtained from 34 adolescents with a history of maltreatment. Results showed that maltreated adolescents with unresolved states of mind in regard to attachment were rated higher on maladaptive behaviour and lower on adaptive behaviour than maltreated adolescents who were resolved. Implications for school-based mental health intervention and future research are discussed. (Contains 3 tables).