Current theories in moral psychology do not agree about the kinds and range of offenses that people should moralize. In this study, a new approach to defining the moral domain, Human Superorganism Theory (HSoT), is presented and tested. HSoT proposes that the primary function of moral action is the suppression of cheaters in the unusually large societies recently established by our species (i.e., human 'superorganisms'). It suggests that a broad range of moral concerns exist beyond traditional notions of harm and fairness, including actions that inhibit functions such as group-level social control, physical and social structuring, reproduction, communication, signaling and memory. Roughly 80,000 respondents completed a web-based experiment hosted by the British Broadcasting Corporation, which elicited a suite of responses to characteristics of a set of 33 short scenarios representing the areas identified by the HSoT perspective. Results indicate that all 13 superorganism functions are moralized, while violations of scenarios falling outside this area (social customs and individual decisions) are not. Several hypotheses derived specifically from HSoT were also supported. Given this evidence, we believe this new approach to defining a broader moral domain has implications for fields ranging from psychology to legal theory.