A teacher's capability to improve students' scientific understanding is influenced by the school and district in which they work, the community in which the school is located, and the larger professional communities to which they belong. This activity provides guidance for schools and districts on how best to support teachers' learning and how to implement programs for professional development. The report makes recommendations for science teachers' learning that take a broad view of what is known about science education, how and when teachers learn, and education policies that directly and indirectly shape what teachers are able to learn and teach.