Professional development of teachers has been a primary strategy for school improvement in many schools. Previous research on professional development has shown that not all teachers are at the same entry point for professional development based upon instructional strengths, needs, interests and existing knowledge. Research also identified that there are certain contexts which promote the professional learning of teachers and could lead to gains in student achievement. This study examined professional development practices in three Wisconsin schools that had achievement gains above the state average while educating a diverse student population. In order to further inform administrators about professional development, data regarding individual teacher professional development and school or district mandated professional development was collected in order to answer two questions: In districts that have shown consistent and significant achievement gains for students, what are the occasions in which teachers learn? What organizational structures, cultures and supports shape teacher investment in professional learning in these districts? New findings found that teachers view teacher learning and teacher professional development as two unique domains with different meanings. Furthermore, teachers sought to become an "expert" in a particular area that then defined who they were as an educator. Finally, teachers valued having a voice in education. Other findings supported previous research: student achievement gains were a main rationale for choosing professional development topics and for measuring the impact of new learning by both teachers and schools/districts. Findings also highlight the structures and roadblocks teachers identified as impacting their professional learning. Teachers valued discourse, active learning and choice as structures for professional development. Time was the roadblock most consistently mentioned to impede professional development. Redundancy was also mentioned as a teacher concern about professional development. Finally, recommendations for administrators who plan professional development opportunities were identified.