Despite recently improved numbers of women and other historically underrepresented groups in STEM (science, technology, engineering, and mathematics) in U.S. higher education, women continue to lag significantly in comparison with men in many STEM disciplines. Female participation is especially low in computer science, engineering, and physics and at the advanced levels in academic STEM—at full professor and in administrative (department head or chair, dean) positions. While there have been various theoretical approaches to explain why this gender gap persists, a particularly productive strand of research indicates that deeply rooted gendered, racialized, and heteronormative institutional structures and practices act as barriers to a more significant movement of diverse women into academic STEM fields. More specifically, this research documents that a hostile academic climate, exclusionary practices, and subtle forms of discrimination in hiring and promotion, as well as lack of positive recognition of female scientists’ work, account for relatively low numbers of women in fields such as engineering, physics, and computer science. Nevertheless, since the early 2000s, numerous initiatives have been undertaken in U.S. higher education to remedy the situation, and some progress has been made through programs that attempt to transform STEM departments and colleges into more inclusive and equitable academic spaces.