This practicum describes the multiple roles and interventions of a school social worker using an ecological/systemic approach with adolescents from vulnerable inner city families. These families were experiencing poverty, abuse, problems with child welfare agencies, and a number of other issues. The main objective of the practicum was to reduce the negative and self destructive behaviours of the adolescents who were part of a classroom for students with behavioural and learning difficulties. A secondary objective of the practicum was to increase both positive coping skills and the self esteem of the adolescents and their family members. As a school social worker, I assumed multiple roles including individual, group and family therapist, consultant to the primary and secondary school staff, and broker of community services. Evaluation attempted to be ecological in nature and included the Child Behaviour Checklist for the adolescent, the family and the teacher. Secondary evaluation measures included the Self Control Rating Scale, and the Hare Self Esteem Scale. Two client feedback forms were also administered, one for the students and one for the families and teachers. The experience of this practicum suggests that a school based intervention which reduces stressors in adolescents' environments, can result in an improvement in their behaviour.