The study explored the ways in which qualified and trainee clinical psychologists perceived professional behaviour, as illustrated in a series of short vignettes, in student and clinical practice contexts. Comparisons were made to identify the extent to which ideas of professionalism differed across different learning contexts and between qualified and unqualified staff, with the aim of adding to the literature on which factors influence the development of professional identity in health professionals. An online questionnaire depicting a range of potentially unprofessional behaviours was completed by 265 clinical psychology trainees and 106 qualified clinical psychologists. The data were analysed using a general linear model with simultaneous entry in which rater (trainee vs qualified clinical psychologist), setting (student vs placement) and their interaction predicted acceptability ratings. We found that, in general, trainees and qualified staff agreed on those behaviours that were potentially unprofessional, although where significant differences were found, these were due to trainees rating the same behaviours as more professionally acceptable than qualified clinical psychologists. Despite trainees identifying a range of behaviours as professionally unacceptable, some percentage reported having engaged in a similar behaviour in the past. Irrespective of the status of the rater, the same behaviours tended to be viewed as more professionally unacceptable when in a placement (clinical) setting than in a student (university) setting. Generally, no support was found for a rater by setting interaction. The study suggests that trainee clinical psychologists are generally successful at identifying professional norms, although they do not always act in accordance with these. Conflicting student and professional norms may result in trainees viewing some potentially unprofessional behaviour as less severe than qualified staff. Health professional educators should be aware of this fact and take steps to shape trainee norms to be consistent with that of the professional group.