Drawing on 3 years of observational, survey, and interview data, this article highlights the importance of communities of practice (Lave & Wenger, 1991) for school staff members supporting Spanish-speaking, newcomer students in large, comprehensive high schools that often lack the resources to directly support this population. We highlight how a research project focused on the implementation and development of a bilingual math and science curriculum across 4 schools in urban and rural California provided teachers, counselors, and school leaders the necessary space and community to know what and how to best serve immigrant, Spanish-dominant students. The article demonstrates how these school staff people leveraged the research project meetings and check-ins with research assistants to share best practices and common challenges across schools and roles when working with newcomer students.