Across time and cultures, envy is widely regarded as a vice. This paper provides a theory of viciousness that explains why envy is a vice. First, it sketches an account of the trait of envy, utilizing some of the social psychology literature on social comparisons. Second, it considers some theories of vices—including Neo-Aristotelian, Kant’s, and Driver’s consequentialism—and briefly argues that they are not adequate in general or with regard to envy. Lastly it articulates a theory of viciousness on which a (...) trait’s degree of viciousness is determined by its disposition to produce actions and attitudes that are of disvalue; it then applies this theory to envy. (shrink)