There is a gender gap in science, technology, engineering, and mathematics (STEM) education. This presents a worldwide problem of inequity. Sociocultural stereotypes associating STEM with males act as barriers that prevent girls from developing interests in STEM. This article aims to show that we can increase equity and enhance outcomes for a broader number of children around the world by integrating psychological and educational science. The article discusses four strands of research in an effort to build a bridge between psychological science and educational practice and policy. First, it describes how stereotypes can act as barriers that prevent girls from developing interests in STEM. Second, it summarizes psychological experiments demonstrating that counteracting stereotypes can increase girls' interest in enrolling in STEM courses. Third, it examines new results showing that children adopt the pervasive stereotypes of their culture starting from surprisingly young ages, and it shows that children's stereotypes influence their academic attitudes and performance. Fourth, it describes innovative practical interventions that can increase and equalize motivation and engagement in STEM for both boys and girls. In each of these sections, the authors link scientific findings with educational applications. Cultural stereotypes contribute to educational inequities, but scientists, educators, and policymakers can together make a difference to reduce stereotyping and boost girls' interest in STEM worldwide.