This report presents a research-action agenda to enhance the role of afterschool education in increasing girls' participation in science, technology, engineering, and mathematics (STEM) courses, majors, and careers. The research-action agenda was developed for three areas: access, recruitment, and persistence; program content, approaches, and strategies; and staff and professional development. The agenda arose from discussions during the Science, Gender, and Afterschool Conference, which took place in Washington, D.C. in September 2002.