This article aims to articulate how criminal justice staff may inadvertently make errors of logic when working with offenders with personality disorder. The aim of this article is also to consider ways of working that might help criminal justice staff to meaningfully engage and motivate clients with personality disorder, properly identify strengths and avoid making these fundamental errors of logic. A way of working is, therefore, outlined which attempts to facilitate consideration of the offender’s inner world, their logic and their experience. As such, this article promotes a psychologically informed approach to criminal justice practice.