Drawing from social identity theory, this research examines scarce gender representation as a contextual condition that inhibits same-gender supervisors' support. Survey results in Study 1 found that when women were proportionally underrepresented, they reported feeling less supported by female supervisors than male supervisors. Study 2 showed that women who perceived they were gender tokens in their organization were less likely to support an outstanding female subordinate than an identical male. Study 3 experimentally tested social mobility as a mechanism for the effects of tokenism on same-gender supervisor support. Results suggest that social mobility and group composition jointly affect ratings of same-gender targets. Perceptions of gender-based social mobility appear to be one mechanism through which tokenism influences same-gender relations at work.