This dissertation examines the impact of a district-wide professional development initiative to foster equitable pedagogies and practices for emergent bilingual students. The initiative spanned five years, 2012-2017, across one of the largest school districts in the Northeast. This quasi-experimental, mixed methods case study was conducted across twelve schools to investigate the efficacy of a sheltered instruction professional development program in three areas: 1) teacher learning and knowledge about sheltered instructional practices (n=1457) and application of the newly learned practices (n=70), 2) student learner outcomes, as measured by a standardized assessment, through three cohorts of third through eighth graders (n=457) and teachers (n=144). Parameters for the three teacher cohorts are defined by levels of professional development completed. All educators throughout the district completed an Initial training, consisting of 15 hours of instruction. A smaller group of educators completed an Advanced training, comprised of 25 hours of instruction with a job embedded component. Lastly, this study synthesizes teachers’ voices that call for specific administrative shifts and supports to effectively implement sheltered practices in the classroom. Student data (n=457) and teacher survey responses (n=1943) were analyzed to forward the conversation about evaluation and sustainability of professional development workshops. Based upon the examination of standardized assessment data, no statistically significant effects were found in the performance of classrooms whose teachers completed 0, 15 or 45 hours of professional development. However, data from teachers surveyed who completed minimally fifteen hours of training illuminated the challenges of using standardized assessments and the lack of district support to effectively implement sheltered strategies. Additionally, teacher surveys highlighted the need for instructional guidance, resources and administrative support required to effect change in implementing and sustaining sheltered pedagogies and practices. In summary, this dissertation study engages with three lines of inquiry by, 1) examining educational equity for emergent bilinguals by (re)defining academic language and access to meaningful instruction, 2) investigating the efficacy of a professional development program aligned with pedagogically sound practices that cultivate language, community and academic achievement, and 3) advocating for alternative approaches in supporting teachers and leadership that engage dual language learners in high quality learning experiences.