Can the culture of STEM help reproduce inequality? Professional cultures, which give each discipline its particular “feel” and unite discipline members under a taken-for-granted system of meanings and values, are not benign. Drawing from several NSF-funded studies, articles, and my recent book, Misconceiving Merit, I argue that these professional cultures can have built within them intersectional inequalities along gender, race/ethnicity, and LGBTQ+ status. I discuss the role of three particular cultural ideologies—the Schema of Scientific Excellence, Depoliticization, and the Meritocratic Ideology—in producing these disadvantages. I end by explaining why decisions (e.g. hiring, promotion) that partially rely on assessments of individuals’ “fit” with professional cultures are particularly important to critically examine for their potential to contribute to inequality.