The Rice University Office of STEM Engagement's (R-STEM) Regional Math Collaborative expands the impact of middle school math teachers by improving STEM instruction within classrooms and schools throughout the Houston metropolitan area. R-STEM provides teachers with comprehensive, year-long professional development (over 100 hours) based on research supported practices. What distinguishes the Rice Regional Math Collaborative from other professional development training programs is its broad impact in terms of teachers and school districts served and our deep focus on STEM content, constructivist pedagogy, and developing teacher-leaders. The Rice Math Collaborative model will provide teachers with a two-week summer institute, evening workshops during the academic year (4), including a lecture series presented by Rice faculty and Houston area scientists, and a STEM-Saturday experience, which will allow participants to work collaboratively and collegially with middle school science teachers. The major objectives are to improve: 1. Teachers’ content knowledge in math with integrated science and as related to the TEKS through STEM learning experiences. 2. Teachers’ instructional skills and practices by encouraging the use of research-based teaching strategies and pedagogical methods of intervention that have been tested and proven to be effective in increasing student learning. 3. Students’ academic achievement in mathematics by providing teachers and students with materials and learning experiences tightly aligned with the TEKS. 4. Teachers’ leadership skills in mentoring, coaching, lesson refinement, unit of study development, and the development of activities that integrate science, math, engineering and/or technology. These major objectives can be accomplished through R-STEM’s intensive professional development program. All program outcomes will be assessed based on a comprehensive evaluation and research plan.