Do the moral sentiments move us to act, according to Hume? And if so, how? Hume famously deploys the claim that moral evaluations move us to act to show that they are not derived from reason alone. Presumably, moral evaluations move us because (as Hume sees it) they are, or are the product of, moral sentiments. So, it would seem that moral approval and disapproval are or produce motives to ... [Show full abstract] action. This raises three interconnected interpretive questions. First, on Hume's account, we are moved to do many virtuous actions not by the sentiments of approval and disapproval, but by other sentiments, such as gratitude and parental love; so when and how do the moral sentiments themselves provide motives to act morally? The second question arises as a result of a position I defend here, that the moral sentiments are best understood as Humean indirect affections. Hume says that the four main indirect passions (pride, humility, love and hatred) do not directly move us to act. The second question, then, is whether their status as indirect affections nonetheless allows moral approval and disapproval to be or provide motives. Finally, if we make a natural assumption about how Hume thinks belief about future pleasure is connected to the desire to obtain it (I call it the signpost assumption), it turns out that the mechanisms for producing motives that most naturally come to mind are ones that are equally available to reason alone. This introduces the third question: given the constraints Hume imposes on the nature of the moral sentiments, is there a way in which they can move us to act that is not also a way in which reason alone does? I argue that, given the signpost assumption, while Hume has greatly constrained his options, his moral sentiments do have one very limited way of moving us to act that is not available to reason alone. However, there are reasons to doubt that Hume endorses the signpost assumption. Without it, our moral evaluations have a far greater capacity to produce motives to act. One important objection arises; but this problem can be solved by rejecting a further assumption about what counts as being produced by reason alone.