Governance structures constrain and enable the actions of public managers. Principal–agent theory has played a dominant role in our understanding of governance structures. This theory suggests that politicians create relatively static governance structures in a top–down fashion and hold managers accountable for mandated results. In other words, public managers are influenced by governance structures but do not affect governance structures. However, we argue that public managers do affect governance structures, and, in order to understand how this influence takes place, we need a new way of thinking about governance structures. We propose thinking about governance structures as relationships created through the interactions of people in different and reciprocal roles that are relatively dynamic. Public managers are an important source of the multiple, reciprocal, and dynamic interactions that produce governance (relationship) structures. As such, managers are accountable not only for policy outcomes, but also for the appropriateness of the relationships they create and support.