Two studies examined the relationship between individual differences in cognitive reflection (CRT) and the tendency to accord genuinely moral (non-conventional) status to a range of counter-normative acts — that is, to treat such acts as wrong regardless of existing social opinion or norms. We contrasted social violations that are intrinsically harmful to others (e.g., fraud, thievery) with those that are not (e.g., wearing pajamas to work and engaging in consensual acts of sexual intimacy with an adult sibling). Our key hypothesis was that more reflective (higher CRT) individuals would tend to moralize selectively — treating only intrinsically harmful acts as genuinely morally wrong — whereas less reflective (lower CRT) individuals would moralize more indiscriminately. We found clear support for this hypothesis in a large and ideologically diverse sample of American adults. The predicted associations were not fully accounted for by the subjects’ political orientation, sensitivity to gut feelings, gender, age, educational attainment, or their placement on a sexual morals-specific measure of social conservatism. Our studies are the first to demonstrate that, in addition to modulating the intensity of moral condemnation, reflection may also play a key role in setting the boundaries of the moral domain as such.