This research extends our understanding of gender bias in leader evaluations by merging role congruity and implicit theory perspectives. We tested and found support for the prediction that the link between people’s attitudes regarding women in authority and their subsequent gender-biased leader evaluations is significantly stronger for entity theorists (those who believe attributes are fixed) relative to incremental theorists (those who believe attributes are malleable). In Study 1, 147 participants evaluated male and female gubernatorial candidates. Results supported predictions, demonstrating that traditional attitudes toward women in authority significantly predicted a pro-male gender bias in leader evaluations (and progressive attitudes predicted a pro-female gender bias) with an especially strong effect for those with more entity-oriented, relative to incrementally oriented person theories. Study 2 (119 participants) replicated these findings and demonstrated the mediating role of these attitudes in linking gender stereotypes and leader role expectations to biased evaluations.