The Tufts University Urban Mathematics and Science Teacher Collaborative is a collaboration among three Tufts University Arts and Sciences departments (Education, Mathematics, and Physics & Astronomy) and three Boston public schools in the 5-12 grade range (Boston Arts Academy, Fenway High School, and Mission Hill School). A local non-profit organization, the Center for Applied Special Technologies (CAST) is providing professional development around Universal Design for Learning (UDL), a framework for designing curriculum and instruction to address barriers to learning. The Collaborative is preparing 16 new Mathematics and Science Teaching Fellows (TFs), and contributing to the development of 4 Master Teaching Fellows (MTFs) over 6 years. It builds on more than 10 years of experience in the preparation of teachers for work in urban schools through the Urban Teacher Training Collaborative (UTTC), a school-based teacher residency program in which pre-service teachers work in their assigned schools full-time for a full academic year under the guidance of mentor teachers and university professors while earning a Master of Arts in Teaching (MAT) degree. Two new courses integrating science and mathematics content with pedagogy are being developed collaboratively by education and STEM faculty in the physics and mathematics departments. Ongoing professional development is provided through the creation of an online community (through Digital Toolboxes and blogs) to encourage communication and discussion among TFs, MTFs, University Participants, and CAST. The courses, course materials, examples of effective teaching, and teacher discussion forums are being built as free, open-source, cross-platform modules that universities and schools can use and modify under Creative Commons licensing. The project seeks to increase teachers' understanding of the challenges of teaching in urban settings; increase the numbers and retention of teachers of Mathematics and Science in urban schools; transform teachers' practices in Mathematics and Science; increase student understanding and performance in Science and Mathematics for students taught by TF and MTFs; and develop stronger relationships with local urban schools.