This paper discusses how policymakers can support teaching to high standards. It explains that teacher education significantly influences teacher effectiveness. The United States offers fewer supports for teacher learning than do other industrialized countries, and many U.S. teachers are inadequately prepared for the classroom. The United States also lacks a true professional development system for teachers. Its fragmentation and variability account for many problems and are largely attributable to three factors (variability in standards for candidates, in standards for programs, and in teacher education curriculum and faculty). Five premises pertinent to improving teachers' learning opportunities include teachers' prior beliefs and experiences affect what they learn, learning to teach to the new standards for students takes time and is difficult, and opportunities for analysis and reflection are central to learning to teach. Four current lines of work hold promise for effective professional development: integrating theory and practice, developing professional discourse around problems of practice, content-based professional development, and learning from analysis of practice. States with top student test scores have long supported high quality teaching and teacher learning. Promising strategies for improving teaching include standards-based reform, redesign of teacher education and induction, and restructured professional development. (SM)