Commonsense morality divides acts into those that are right and those that are wrong, but it thinks some wrong acts are more seriously wrong than others, for example, murder than breaking a promise. This has several implications. If an act is more seriously wrong, you should feel more guilt about it and, other things equal, you are more blameworthy for it and can deserve more punishment; we may also need to consider serious wrongness when choosing in conditions of risk or moral uncertainty. This paper examines how one act can be more seriously wrong than another, and, when it is, what makes this so. More specifically, it considers a number of different views about the ground of serious wrongness and explores the possibility that this may be different when acts violate deontological versus consequentialist duties. It also asks whether there is a parallel concept that admits of degrees on the side of rightness, one of being, as we can say, more importantly right. It aims to expand the scope of deontic theory from binary questions about right versus wrong to ones whose answers admit of degrees.