This study investigated whether elements of Social Identity Theory (SIT) and Self-Categorization Theory (SCT) appropriately described experiences of bisexual people in terms of accurately predicting the effect of self-stereotyping on well-being. Previous research has indicated that self-stereotyping is protective for members of marginalized groups. This study manipulated prototypicality, or self-stereotyping, to determine whether it affected well-being for bisexual-identified people. Forty-two bisexual participants were told either they were a strong or weak representation of a prototypical bisexual person, after which several well-being measures were taken. Female participants reported significantly higher levels of negative affect in the high prototypic group, indicating SIT and SCT may not operate the same way for bisexuality as they do for other social identities.