This study aimed to investigate professional staff attitudes and knowledge about adolescents who engage in self-harming behaviour and to identify training needs. Previous research has suggested that medical and health care staff perceptions may reinforce the stigma associated with such behaviour and therefore jeopardise the effectiveness of interventions. To date, no available research exists on the views of school teachers. Participants recruited for the study were 120 qualified professionals working within an Accident and Emergency Department (A&E), Child & Adolescent Mental Health Services (CAMHS) and a Secondary School, based within the West Midlands, United Kingdom. Results demonstrated statistically significant differences between the groups. CAMHS staff were more knowledgeable and felt more effective than either A&E staff or teachers, whereas A&E staff expressed more negative attitudes. 95% of all staff reported that they would benefit from further training. These findings are discussed in relation to practice issues. (Contains 3 tables.)