This paper begins by presenting some of the research findings about the importance of afterschool and other OST experiences for STEM learning. It then proceeds to summarize evaluation data from a selection of strong afterschool STEM programs and describes the types of substantive impacts these programs are having on participating youth. The paper concludes with recommendations for how we can construct an integrated approach to education that includes in-school and OST experiences. Appendices provide details of the programs whose outcomes are featured in the narrative. (author abstract)