Dual Language programs have been adopted by many school districts in efforts to provide students with a bilingual, biliterate, and cross-cultural education. These programs not only aim to maintain students’ native language while learning a second language, but also attempt to close the achievement gap for English Language Learners (ELLs) and other students of color. In attempt to achieve such important goals, schools often adopt programmatic changes in absence of district support or research based guidelines. Dual language schools who are not following specific dual language guidelines continue to see widening disparities in achievement as the schools transition to more rigorous Common Core State Standards. Research shows that successful dual Language schools must have standards based curriculum, a focus on building teacher knowledge and skill around biliteracy and provide structured learning opportunities for teacher collaboration. This action research sought to build teacher capacity at a Spanish dual school in a low income neighborhood through PLCs and professional development. I facilitated two grade level PLCs to increase teacher content knowledge of the new Adelante and Advance dual language curriculum by Benchmark Learning and increase teacher collaboration and planning in support of student’s second language acquisition. This process lead to the creation of a unit planner tool designed to facilitate the planning across the Spanish and English classroom. I found that the intervention resulted in an increase in teacher collaboration, a deeper understanding of biliteracy strategies and a higher comfort level in implementing the new ELA and SLA curriculum.