My central claim in this work is that vanity plays a fundamental role in Hume's account of moral motivation, a role that is almost entirely overlooked by contemporary scholars. Hume's moral psychology is typically viewed as a straightforward internalism, where motivation is built directly into the acceptance of a moral evaluation. Other scholars, reacting against this reading, insist that for Hume moral evaluations motivate only indirectly. I reject both of these accounts of Hume's view of moral motivation as inadequate, and replace them with an explanation that gives vanity its due place. I start by defining the concept of vanity and by showing its relevance to Hume and his contemporaries. I then argue that vanity serves for Hume both as a supporting motive to virtuous action and as an initiating motive for a moral education. Given the contribution vanity can make towards becoming a virtuous person, it is sensible that Hume would regard vanity as itself a virtue, though he does this only in a cautious or subtle way. Finally, I contend that moral motivation by vanity does not, on Hume's view, take away from the virtue or moral worth of the action.