This single-district, case study builds a conceptual understanding of the role of the school district in improving educational opportunities and outcomes for adolescent English learners. As the numbers of English learners grow at a faster rate than that of the general school population, and many continue to struggle with the challenges of mastering English proficiency and academic content, the need for district leaders to develop a deeper understanding of strategies for educating these students more effectively assumes increasing urgency. Several questions guide this study: What contextual factors influence district efforts to promote and support English-learner-focused reforms in secondary schools? What roles, systems, strategies, and practices does the district employ in creating more equitable educational opportunities and outcomes for English learners? In its efforts to address the needs of adolescent English learners, how does the district negotiate the change process? What lessons can districts learn about their roles in supporting the achievement of adolescent English learners? Findings were derived from interviews with district leaders, principals, teachers, school staff, and parents; observations of classrooms and district-training activities; and document analysis. Grounded in the literature on the district's role in reform and the education of English learners, the study presents a theoretical framework for district-led change on behalf of adolescent English learners and provides a rubric that merges district roles in reform with research-based practices for educating English learners. Together, these complementary instruments capture the complex nature of this work. This research demonstrates that district leadership on behalf of English learners involves the execution of multiple, interdependent roles; a deep understanding of effective practice in working with these students; careful attention to the change process; and a commitment to social justice leadership. It concludes that district latitude for action is considerable and represents a significant opportunity to lead change on behalf of English learners. Potential benefits of this study include enhancing our understanding of district practices yielding the greatest returns for currently underserved students; focusing attention on existing district will and capacity to support reform focused on English learners; and laying the groundwork for future research into how districts facilitate the achievement of specific subgroups.