Person Focused Training is introduced as a model of service delivery for people with severe challenging behaviours. It is defined as training and supporting staff to conduct functional assessments and to design and implement positive behavioural support for specific individuals with challenging behaviours. Longitudinal outcome data are presented from 138 behaviour support plans developed by staff over a seven year period were analysed to determine reductions in frequency of challenging behaviours. Degree of behaviour change was determined across topography of behaviour, gender, age, level of disability, location of residence and role of course participant. Results indicate that the implementation by staff of behaviour support plans are associated with significant improvement in 77% of cases at an average follow-up of 22 months after implementation of support plans. Only location of residence was identified as related to reduction in challenging behaviours with large residential centres being associated with lower rates of behavioural improvement. It is argued that Person Focused training may represent an alternative to existing models of supporting individuals with challenging behaviours. The implications of front-line staff designing and implementing behaviour support plans for the organisation of services and the role of the clinical psychologist are considered.