Existing models of the principal–agent relationship assume the agent works only under extrinsic incentives. However, many observed agency contracts take the form of a fixed payment. For such contracts to work, the principal must trust the agent to work in the absence of incentives. I show that agency fosters the advent of intrinsic motivation and trustworthy behavior. Three distinct motivational schemes are analyzed: norms, ethical standards, and altruism. I identify conditions under which these mechanisms arise and show how they promote trust. The analysis alters several important predictions of conventional models: (1) Better outcomes may ensue in highly uncertain environments; (2) the principal is better off the more the agent is risk averse; and (3) larger equilibrium extrinsic incentives need not be associated with larger effort or larger total surplus.