Past research consistently suggests that singles are stigmatized, but do they constitute a stigmatized group? The current research provides deeper insight into the stigmatization of single people by understanding their ‘group-y’ nature, and how group identification and perception map onto discrimination and prejudice. Study 1 examined the extent to which singles identify as part of a group. Participants were assigned a novel minimal group identity and then completed measures of group identification for four group memberships (e.g., minimal group, relationship status, sexual orientation, nationality). As hypothesized, singles' identification with other singles was lower compared to their identification with other identities—as well as compared to partnered people's group identification. Contrary to our hypothesis, singles did not perceive less discrimination towards singles relative to other aspects of their identity. Study 2 examined the extent to which singles are perceived as a group and the extent to which their group-y-ness vs. perceived responsibility for their group membership explains the acceptability of prejudice towards them. Participants completed measures of entitativity and perceived responsibility for similar out-group identities as in Study 1 (e.g., single people vs. people in romantic relationships). As hypothesized, singles were rated lower in entitativity than people in romantic relationships and other groups. Prejudice towards singles was also more acceptable than prejudice towards national and sexual orientation groups. Accordingly, perceived responsibility was a stronger predictor of the acceptability of prejudice towards singles than their entitativity. We discuss the importance of group-based theoretical perspectives for understanding the current and future stigmatization and well-being of singles.