Gordon Allport (1954) proposed that belief in group essences is one aspect of the prejudiced personality, alongside a rigid, dichotomous and ambiguity-intolerant cognitive style. We examined whether essentialist beliefs—beliefs that a social category has a fixed, inherent, identity-defining nature—are indeed associated in this fashion with prejudice towards black people, women and gay men. Allport's claim, which is mirrored by many contemporary social theorists, received partial support but had to be qualified in important respects. Essence-related beliefs were associated strongly with anti-gay attitudes but only weakly with sexism and racism, and they did not reflect a cognitive style that was consistent across stigmatized categories. When associations with prejudice were obtained, only a few specific beliefs were involved, and some anti-essentialist beliefs were associated with anti-gay attitudes. Nevertheless, the powerful association that essence-related beliefs had with anti-gay attitudes was independent of established prejudice-related traits, indicating that they have a significant role to play in the psychology of prejudice.