Project Summary/Abstract Science, technology, engineering, and math (STEM) leaders across the country have called for more effective ways to train K-12 teachers in pedagogy aligned to the Next Generation Science Standards (NGSS). While NGSS holds promise as an engaging way for students to build authentic science skills and conceptual knowledge, implementation is limited by the degree to which teachers can be trained in new, significant pedagogical shifts. This is especially true for K-5 teachers who have low confidence teaching science and, accordingly, devote little time to science instruction. This problem is especially acute in urban schools with insufficient resources to meet NGSS training needs. This threatens NGSS coherence across grade levels. We must develop effective, efficient NGSS training models if we are to realize our long-term goal of a well-trained, diverse STEM and healthcare workforce. Prior NIH-funded research from our group developed a highly effective model of introductory-level NGSS training for elementary teachers. The current proposal, ESTELE - Elementary Science TEacher LEaders, builds on this work by accelerating the pace at which elementary teachers can be trained through a new science teacher leader (STL) program. ESTELE fully integrates STL training with introductory-level training via am authentic “practicum” training experience in which STLs support novice teachers as they learn and implement NGSS instructional practices by teaching elementary youth in a summer STEM camp. In this way, teacher leaders gain important leadership and coaching skills, while novice teachers learn NGSS pedagogy. STLs then apply their skills during the academic year in their schools, working in support of their peer teachers to build a broader school culture receptive to NGSS reform. The project’s evaluation plan will assess the degree to which this dual-training model is effective in training teachers of different entering skill levels, the effectiveness of STLs providing NGSS training for novice teachers at their schools, and the degree to which these activities help build a school culture receptive to NGSS instructional practice. This proposal is responsive to key NIH-SEPA priority areas including (1) Adaptations of successful SEPA programs in new locations or with new populations, and (2) Embedded math and reading content for projects targeting P-8 Students. In total ESTELE will train a total of 96 elementary teachers in Chicago Public Schools: thirty-two science teacher leaders and sixty-four new-to-NGSS teachers. It will also support high-quality summer learning for 240 underserved youth at Boys & Girls Clubs of Chicago, and high-quality academic year NGSS instruction for up to 7,050 youth in life sciences curricula.