Forensic psychiatric care must be provided within the least restrictive setting possible, whilst simultaneously maintaining appropriate levels of security. This presents particular challenges for the design of forensic psychiatric hospitals, which are required to provide both a therapeutic and a safe material environment, often for extended periods of treatment and rehabilitation. By taking into consideration variable trends in psychiatric service provision and myriad clinical, legal and ethical issues, interdisciplinary forensic facility design teams are at the very forefront in implementing the latest developments in medical architecture. Also, although there are significant differences in how forensic psychiatric services are organized around the world, the underlying clinical challenges and increasingly research-based treatment principles are similar worldwide; it is therefore becoming less acceptable to operate and develop national forensic services without reference to international standards. Accordingly, we here review the literature on what features of forensic psychiatric facilities best serve the needs of those patients who need to rely on them, and we present a systematic and widely applicable approach to the complex and costly challenge of modern forensic psychiatric hospital design.