With their knowledge and expertise in applying psychology to forensic settings, clinical psychologists have a unique role in the promotion of offenders’ psychological well-being and the management of custodial and reoffending risks among offenders. In 1976, under the advice of the United Nations advisor Dr Robert Andry, the then Prisons Department of Hong Kong, recognising the need for such expertise in the rehabilitation of offenders, began to set up psychological services within the department, initially with only one clinical psychologist in post. After 40 years of development, the Correctional Services Department (CSD) of the Hong Kong Special Administration Region now has a much bigger professional team of close to 30 clinical psychologists and also close to 30 officers providing services to persons in custody (PIC) 1 as well as to staff in the department. Given the limited labour poweravailable when the services were first introduced, the focus was on crisis intervention and the prevention and management of custodial risks (i.e., self-harm and violent behaviours). Initially, young offenders were identified as the targets for more focused psychological services as it was hoped that early intervention might bring about the necessary changes to curb their criminal development. Over the years, the services have become more specialised in providing necessary interventions for different groups of offenders, such as sex offenders, violent offenders, young offenders, drug abusers, and women offenders. In the last 20 years, with the development of an empirically based framework for risks and needs evaluation and the management of offenders, more locally developed actuarial reoffending risk assessment tools as well as evidence-based treatment programmes have been launched. This chapter first summarises the development of psychological services in four major areas, namely: (a) forensic assessment for the courts and other statutory bodies; (b) psychological treatment programmes; (c) the management of PIC with a custodial risk, mental health problems, and adjustment difficulties; and (d) the provision of consultation services to management and staff. It then discusses essential elements for the development of effective psychological services and future development directions.