Health systems that aim to secure universal patient access through a scheme of prepayments—whether through taxes, social insurance, or a combination of the two—need to make decisions on the scope of coverage that they guarantee: such tasks often falling to a priority-setting agency. This article analyzes the decision-making processes at one such agency in particular—the UK’s National Institute for Health and Care Excellence (NICE)—and appraises their ethical justifiability. In particular, we consider the extent to which NICE’s model can be justified on the basis of Rawls’s conception of “reasonableness.” This test shares certain features with the well-known Accountability for Reasonableness (AfR) model but also offers an alternative to it, being concerned with how far the values used by priority-setting agencies such as NICE meet substantive conditions of reasonableness irrespective of their procedural virtues. We find that while there are areas in which NICE’s processes may be improved, NICE’s overall approach to evaluating health technologies and setting priorities for health-care coverage is a reasonable one, making it an exemplar for other health-care systems facing similar coverage dilemmas. In so doing we offer both a framework for analysing the ethical justifiability of NICE’s processes and one that might be used to evaluate others.