Is gratitude a moral virtue?

One matter upon which the already voluminous philosophical and psychological literature on the topic seems to be agreed is that gratitude is a psychologically and socially beneficial human quality of some moral significance. Further to this, gratitude seems to be widely regarded by positive psychologists and virtue ethicists as a moral virtue. This paper, however, sets out to show that such claims and assumptions about the moral character of gratitude are questionable and that its status as a moral virtue is by no means straightforward.