This study evaluates the outcomes of short interagency training courses provided by six Local Safeguarding Children Boards in England. The aim was to develop practical skills in recognising and responding to the needs of children with harmful sexual behaviour in an interagency context. The courses all employed interactive learning and teaching methods as well as presentations of case studies, research findings and statutory guidance. Professionals (n = 147) from a range of agencies participated in the evaluation. Their attitudes, knowledge and self-confidence were assessed using a specially designed 20-item self-report scale. Scores at registration 6 weeks in advance and at the start and end of the course were compared in a double-baseline, time-series design. There was strong evidence of overall improvements in scores on most of the scale items, which are attributable to the course. However, concerns are also raised about the small numbers of criminal justice professionals participating compared to child welfare professionals.