Abstract
"This paper is part of the special issue on Teacher Learning and Practice within Organizational Contexts." Theorizing and exploring teacher learning contexts is critical to understanding reform-based instructional changes. Research on professional learning, organizational contexts, and science reform has grown over the years, particularly since the unveiling of the Framework for K-12 Science Education in the United States. In this article, the authors present the case of Mr. Gray-a veteran middle school science teacher-to explore factors that influence the implementation of professional learning tools and resources. Using the theoretical constructs of habitus, structure, and agency, the study offers insight into the acquisition of reform-aligned teaching practices and illuminates why it is challenging to change science pedagogy. While professional learning was a supportive structure, especially for availing new schemas and supporting agency, this paper highlights the importance of considering agency-related constraints beyond professional learning. Students' ways of participation, assessments, and a teacher's existing habitus were found to be influential structures that constrained Mr. Gray's agency toward reform. The authors argue that structures have differential power in influencing change and that structures may work together in unpredictable ways, across different teaching contexts, to limit or facilitate change of teaching habitus. The interplay of habitus, structure, and agency explored in this research has implications for professional learning design and teacher education programs.