This mixed-methods study aimed to develop understanding of professionalism in the Vocational Education and Training (VET) sector in Ireland through exploring the nature of practice and practitioners, and how practitioners conceptualise and construct professionalism and develop as professionals in the VET workplace. This was done using a conceptual framework incorporating workplace learning theories to provide a fresh way to consider how VET trainers are prepared for professional practice (i.e. Lave and Wenger, 1991; Fuller and Unwin, 2004) It emerged from the study that trainers perceived their role primarily in terms of preparing learners for the labour-market. Novice trainers were rapidly immersed in their new roles and the workplace context experienced by them appeared to have inadvertently encouraged them to hold onto former occupational identities, in many cases prioritising subject-matter expertise over pedagogic knowledge. It also emerged that the trainers’ ourney from newcomer to competent or expert practitioner was dependent n the learning environment they experienced and that their progress was nfluenced by ‘expansive’ and ‘restrictive’ characteristics (Fuller and nwin, 2004). As the study progressed it emerged that Fuller and Unwin’s heory became much more significant than was originally envisaged when developing the conceptual framework. Professionalism was predominantly constructed by many trainers as ‘structure’ with a focus on the achievement of targets and outcomes (Gleeson and Knights, 2006). The study concluded that there is a challenge for VET providers to make workplace learning more visible and to enable it to take place in a more expansive environment. A new model of professionalism is proposed which integrates formal and informal professional learning in the workplace. This study contributes to the research by: generating a profile of current VET trainers which outlines their qualifications and experience and the nature of their work; developing an understanding of practitioners’ perception of the nature of their practice, competence and professionalism and their experience of entry to and professional development in the VET sector; and, providing a model of the dominant construct of professionalism emerging from the practitioners who participated in the study and suggesting an alternative model of professionalism for VET.