In 2012, the European Commission launched the campaign Science: It’s a girl thing!, aimed at encouraging women to choose research careers, as they are sorely underrepresented in science, technology, engineering, and mathematics (STEM). Given that gender disparities in aptitude for specific fields are generally very small, highly gendered skewness in educational choices suggest pathways dictated by stereotypes rather than abilities, leaving valuable STEM talents unused. Many European countries have invested in boosting girls’ participation in STEM through workshops with girl-oriented science topics, contact with female role models, and information packages. However, the vast majority of these initiatives have not been scientifically evaluated. Further, most programs leave untouched one of the key underlying processes keeping girls from STEM that emerge from the research literature, namely daily socialization reinforcing gender stereotypes in the school and family context. The project aims to fill this gap by studying sources of gender stereotyping in the school setting, in materials such as school books, classroom organization, gender of teachers, and teacher implicit bias. In addition the project will longitudinally investigates salient family processes from infancy to late adolescence to inform parent education programs. This approach is innovative because it is the first to systematically study multiple sources of gender stereotyping in the school setting in both primary and secondary education, and the family study is unique because it includes children and adolescents across development in both the school and the family context. The insights from this study will provide new avenues for both research and practice regarding gender socialization. The project fits seamlessly with my expertise in gender socialization, and experience with longitudinal and RCT projects in schools and families