It has long been suggested that gender stereotyping undercuts support for female candidates, yet a growing number of studies—including several analyses of Hillary Clinton’s 2008 presidential campaign—find limited evidence of such effects. By contrast, I find consistent evidence of voter gender bias using an alternative approach based on perceptions of group favoritism. Using new survey measures included on a nationally representative panel survey fielded during the 2008 US presidential primaries, I find that many citizens perceive female elected officials as likely to steer government resources toward women, a behavior that most evaluate negatively. Moreover, fear of gender favoritism predicts opposition to Clinton throughout the 2008 Democratic primary campaign, as well as in a hypothetical general election matchup with the Republican nominee.