Standard economic models of tax compliance have focused on enforcement-driven compliance. Notably, tax administrators also tend to place a great deal of emphasis on the importance of improving "tax morale" by encouraging voluntary compliance, creating a culture of compliance, and changing social norms. Tax morale does indeed appear to be an important component of compliance decisions, and there is strong evidence that tax morale operates through a variety of underlying channels. There is less evidence - to date - that indicates we know how to leverage these channels to improve compliance and revenue collection in a consistently successful way.