This paper provides a realist evaluation of the Open Justice virtual reality (VR) smartphone app, designed to develop presentation skills for students on an undergraduate legal education module. This work addresses two research questions: what proportion of students engaged with the Open Justice app, and what worked for whom in what circumstances and why? Questionnaire and interviews were conducted and analysed using a realist evaluation approach. This approach is particularly pertinent to the evaluation of how emerging educational technologies are used, as it can point to the potential affordances of a technological intervention, in addition to assessing its current use. In keeping with the realist evaluation approach, data analysis was completed using the context--mechanism--outcome framework. The findings suggest that more than half of students did not engage with the app during their studies, but this was not surprising as it was a pilot project into using VR with our students and such innovations can be difficult to manage in distance education contexts. Those who did engage with it recognised the potential of immersive VR to contribute to legal skills development, but they found the application of the technology, in this context, to be of limited use. By utilising a realist evaluation framework, this study contributes to the emerging field of programme theory-based evaluations of educational technology, which might form the basis of further research.