This chapter discusses the effectiveness of current professional development programmes for teachers of students with autism spectrum disorder (ASD) in Hong Kong. The article first introduces the available services for students with ASD. The Resource Teaching Programme has been the major service provided by special schools since 1984. The principle of teaching students with special educational needs (SEN) in the least restrictive settings has rendered a rapid growth of the population of students with ASD in ordinary schools in the last decade, causing concern among the teachers. Different tiers of professional development programmes have been developed to equip teachers in ordinary schools with the knowledge and skills needed in dealing with students with SEN. However, these programmes are mainly short term and transmitted directly from the top down. The lack of opportunity to practise newly acquired knowledge and skills in real environments cannot provide sufficient confidence for teachers to handle students with ASD independently. The final part of this chapter provides a recommendation for a collaborative mode of professional development that can assist teachers in gaining practical experiences in a field-based training programme. Copyright © 2022 Springer Nature Singapore Pte Ltd.