Afterschool programs that provide strong science, technology, engineering and math (STEM) learning experiences are making an impact on participating youth not only become excited and engaged in these fields but develop STEM skills and proficiencies, come to value these fields and their contributions to society, and--significantly--begin to see themselves as potential contributors to the STEM enterprise. This paper begins by presenting some of the research findings about the importance of afterschool and other out-of-school-time (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 an integrated approach to education that includes in-school and OST experiences can be constructed. Appendices provide details of the programs whose outcomes are featured in the narrative. They include: (1) Framework of Youth Outcomes; (2) Descriptions of selected afterschool STEM programs with strong youth outcomes; and (3) Selected evaluation results of afterschool STEM programs with strong youth outcomes.