Based on the second wave of the Citizen Political Ambition Panel Study, we provide the first thorough analysis of how gender affects women and men's efficacy to run for office. Our findings reveal that, despite comparable credentials, backgrounds, and experiences, accomplished women are substantially less likely than similarly situated men to perceive themselves as qualified to seek office. Importantly, women and men rely on the same factors when evaluating themselves as candidates, but women are less likely than men to believe they meet these criteria. Not only are women more likely than men to doubt that they have skills and traits necessary for electoral politics, but they are also more likely to doubt their abilities to engage in campaign mechanics. These findings are critical because the perceptual differences we uncover account for much of the gender gap in potential candidates’ self-efficacy and ultimately hinder women's prospects for political equality.