The duty to observe the requirements of procedural fairness is well settled in Australian administrative law. So too is the variable content of that duty and the possibility that it may be limited or excluded by legislation expressed in suitably clear terms. One key aspect of fairness that is not yet clear is its purpose. Why do courts require those who exercise public or official power to act fairly? The question cannot be fully answered by reliance on legislative intent or reference to the common law because recourse to one or both of these possible sources of the duty to act fairly does not necessarily answer why that duty is drawn from the common law or implied as part of statutory interpretation. This article examines recent steps by courts and commentators that suggest an exploration of the purpose of fairness may be beginning to occur.