OBJECTIVE: Entrustable professional activities (EPAs) are used as clinical activities in postgraduate psychiatry training in Australasia. This study aimed to explore psychiatry trainees' perceptions of the impact of EPAs on their motivation and learning. METHODS: A constructivist grounded theory approach was used to conceptualize the impact of EPAs on trainees' motivation and learning. A purposive sample of trainees was recruited from across New Zealand. Semi-structured individual interviews were used for data collection and continued until theoretical saturation was reached. RESULTS: The impact of EPAs on learning was mediated by the trainee's appraisals of subjective control, value, and the costs of engaging with EPAs. When appraisals were positive, EPAs encouraged a focus on particular learning needs and structured learning with the supervisor. However, when appraisals were negative, EPAs encouraged a superficial approach to learning. Trainee appraisals and their subsequent impact on motivation and learning were most affected by EPA granularity, alignment of EPAs with clinical practice, and the supervisor's conscientiousness in their approach to EPAs. CONCLUSIONS: To stimulate learning, EPAs must be valued by both trainees and supervisors as constituting a coherent work-based curriculum that encompasses the key fellowship competencies. If EPAs are to be effective as clinical tasks for learning, ongoing faculty development must be the leading priority.