Increasing attention is being paid to best practice in mental health sciences. One crucial aspect of this is the extent to which the mental health workforce has the knowledge and skills to implement state-of-the-art interventions. Recently, evidence has indicated that sexual offending often begins in adolescence, can be a persistent disorder when left untreated, and is associated with a range of other mental health problems in the perpetrator and subsequently in victims. A small number of evaluations of treatment programs are appearing but little work has appeared addressing the issue of how the workforce is equipped, or can be trained, to work with this challenging population. In this paper we present data on the effects of training on knowledge, skills, confidence, and willingness, to work with this client group. Trainees were 107 mental health workers who attended training workshops provided throughout Queensland, Australia by the Griffith Adolescent Forensic Assessment and Treatment Centre. Results showed that the measures developed for assessing training effects were change sensitive and valid. Training was associated with increases in self-rated skills, confidence, knowledge, and willingness to work with this population, and these changes were maintained for the follow-up sample.