Visionary corporate and educational partners, plus committed community leaders, plus engaged non-profits, equals the Mentor Allentown Coalition, with an ambitious mission to elevate youth through science, technology, engineering, and math (STEM) mentoring. Our group of 50 organizations, led by the Da Vinci Science Center, began work in Allentown in 2014 as one of three Grand Prize winners in the US2020 City Competition. We are the backbone of a collective effort to create new high-impact STEM mentoring opportunities for students of color, high poverty, and girls. We introduce mentoring to existing high-impact programs, deepen existing mentor programs to increase impact, and promote the development of new programs.