Stereotype threat can vary in source, with targets being threatened at the individual and/or group level. This study examines specifically the role of self-reputational threat in women's underperformance in mathematics. A pilot study shows that women report concerns about experiencing self-reputational threat that are distinct from group threat in the domain of mathematics. In the main study, we manipulated whether performance was linked to the self by asking both men and women to complete a math test using either their real name or a fictitious name. Women who used a fictitious name, and thus had their self unlinked from the math test, showed significantly higher math performance and reported less self-threat and distraction, relative to those who used their real names. Men were unaffected by the manipulation. These findings suggest that women's impaired math performance is often due to the threat of confirming a negative stereotype as being true of the self. The implications for understanding the different types of threats faced by stereotyped groups, particularly among women in math settings, are discussed.