Political philosophers have mainly engaged in normatively assessing public institutions by investigating their founding values, notably social justice and political legitimacy. The normative properties that make those institutions well-functioning have been scantly studied. But even when public institutions are established on just and legitimate grounds, it seems crucial to consider how those institutions should work to live up to their grounding reasons. In this article, we argue that the well-functioning of public institutions is premised on the establishment of an institutional ethics of office accountability. This ethics concerns the mutual duties of officeholders when they exercise their power of office in their institutional capacity.