Gender stereotypes that associate science and technology to men more than women create subtle barriers to women’s advancement in these fields. But how do stereotypic associations, when internalized by women, relate to their own sense of fit and organizational commitment? Our research is the first to demonstrate that, among working engineers, women’s own gender stereotypic implicit associations predict lower organizational commitment. In a sample of 263 engineers (145 women), women (but not men) who implicitly associated engineering with men more than women were less committed to their organization. This relationship was mediated by lower self-efficacy and value fit, and not explained by other personality, demographic, or organizational factors. We discuss how internalized cultural biases can constrain women’s experiences in STEM.