Included here are the materials from the first Afterschool STEM Summit, held in Washington DC on September 29. Supported by the C.S. Mott Foundation and the Noyce Foundation, the Summit brought together stakeholders from all 50 states to discuss the potential of STEM in out-of-school time. The agenda delved into the intersections and partnerships among in-school and afterschool and summer STEM learning opportunities and featured remarks from business leaders, education stakeholders and STEM partners. The plenary presentation slides contain useful statistics on STEM interest and pursuit among young people, STEM job projections, and the demographics of STEM professionals. Other slides focus on advocacy, communications, partnerships, system building and ecosystems.