The JumpStarting STEM Pilot was a one year project aimed at increasing the frequency, intensity, and duration of high-quality Science, Technology, Engineering and Mathematics (STEM) learning opportunities for students in California’s publically funded after school programs. With support from the California Department of Education’s After School Programs Division, the AfterSchool Network has implemented a pilot effort operating in 17 after school programs in all 11 regions throughout CA (see appendix A), representing over 280 sites (see appendix B). Participating programs received access to curriculum and ongoing in-person and virtual professional development. These efforts supported site level implementation of 30-60 hours of quality STEM curricular programming with consistent student participation. Staff survey results indicated positive feedback from the in-person as well as virtual professional development offered by the California AfterSchool Network Professional Development Team.