The number of students who are labeled as having some form of behavioural disorder which requires specialized assistance in the regular school setting is growing. Current approaches to working with these students are often based on the standardized application of treatments designed to modify general symptoms rather than specific behaviours. It is noted that this approach to behaviour-change is limited because it does not seek to understand the reasons why particular behaviours are being used by students in particular settings. This paper will present an idiographic framework as an alternative approach to creating meaningful and long-term changes in the behavioural difficulties which occur in the school setting. This approach is based on developing a clear understanding of the purpose and usefulness of difficult student behaviour by investigating how that behaviour assists the student in gaining access to valued outcomes. Of particular significance to this assessment and intervention framework is the inclusion of the student's perceptions about the difficult behaviour and its impact on self, the environment and others. It is argued that effective changes in behaviour can only occur when the student's specific difficulties are understood and the student is taught specific skills to overcome these in the school setting.