While American physicians have traditionally practised as non-unionised professionals, there has been increasing debate in recent years over whether physicians in training (known also as interns, residents or house staff) are justified in unionising and using collective action. This paper examines specific ethical criteria that would permit union action, including a desire to ameliorate patient care as well as the goal of improving the conditions of working physicians. We posit that traditional rebuttals to physician unionisation often lean on an infinite conception of a doctor’s energies and obligations, one that promotes burnout and serves to advance the financial motives of hospital management and administration. Furthermore, this paper explores the empirical justifications for collective action, which include substantial reductions in medical error. Finally, we address the free-rider problem posed by non-union physicians who might benefit from working improvements garnered through union action. We conclude that in order to maintain a notion of justice as fairness, resident physicians who benefit from union deliberations are impelled to acquire union membership or make a commensurate donation and that the healthcare organisations for which they work ought to share in the responsibility to improve patient care.