FASD, along other cognitive impairments, is relevant to whether an accused person is fit to stand trial for an alleged offence. While differences exist between jurisdictions, a person found unfit to stand trial in Australia may be detained – often indefinitely and in a custodial setting – for a longer period than if they had plead guilty to the offence. The application of fitness to stand trial regimes to persons with FASD and other cognitive impairments has been criticised by international bodies, parliamentary committees, the judiciary, disability advocates, and researchers. Using case studies, this chapter outlines the challenges legislative regimes governing fitness to stand trial pose for persons with FASD and other cognitive impairments. It will explore decolonising reform options to improve outcomes for unfit accused with FASD through a multidisciplinary and community-focussed approach, drawing on international best practice examples – including the new FASD Court in Manitoba, Canada, and the New Zealand needs and cultural assessment model.