The purpose of this case study was to provide insight into the challenges educational leaders face in their efforts to improve teaching and learning for English language learners within a context of increased testing and accountability. I examine the assumptions underpinning leadership practices to understand how teacher quality and student learning is being interpreted, assessed, and addressed in an under-resourced, low performing school serving predominantly Spanish speaking students. Overall this study analyzes how school leadership impacts teacher quality reform and furthers our understanding of what it takes to expand educational opportunity for English language learners. This study was guided by four primary research questions: (1) How do administrators and teachers make sense of increasing pressures to enhance teacher quality and improve student learning? (2) How do they believe they can expand opportunities to achieve for economically impoverished and linguistically diverse learners? (3) What assumptions underpin the policies and practices they implement? (4) Finally, how do these assumptions play out in the everyday practices of administrators and teachers at Nieberg Elementary? Over a period of six months, I conducted formal and informal interviews, observations and document analysis to understand how administrators and teachers believe they can increase opportunities to achieve for English language learners. The theoretical lenses of Amartya Sen (1999) and Paulo Freire (1970) framed the analysis of this study and provided insight into the political, social, economic, and cultural context that is shaping contemporary education reform and influencing policies, programs, and practices in today's classrooms. The Principal of Nieberg Elementary believes that she can improve learning and increase students' opportunities to achieve by: (a) focusing on developing English language competency; (b) replacing bilingual teachers with English only teachers; (c) implementing a standardized and rigidly implemented curriculum; and d) asserting greater administrative authority over administrators and teachers in the building. The findings of this study reveal that these approaches to improving teaching and learning arose within the pressure cooker context of high stakes testing and mandated achievement; and thus, limited the real opportunity ELL students had to achieve. The findings of this study reveal the logic and limits of focusing on achievement alone to expand educational opportunity for English language learners. For one, this case study reveals the pressure that educators feel to move Spanish-speaking children into English language competency quickly so that they can pass mandated achievement tests. This effort to force faster learning, however, resulted in very little achievement and a lot of frustration for administrators, teachers and children. The administrators and teachers at Nieberg feel that they, like their students, are being forced to fail in a context of education reform that does not address or honor the learning process and educational needs of children who do not speak English. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]