Using a randomized controlled trial, we tested a new teacher professional development program for increasing the language and literacy skills of young Latino English Learners with 45 teachers and 105 students in 12 elementary schools. School-based teams randomly assigned to the intervention received professional development focused on cultural wealth, high-impact instructional strategies, and a framework for collaboration. We observed each teacher three times during the school year and assessed students individually at the beginning and end of the school year using the Woodcock Muñoz Language Survey (WMLS). Using an Intent-To-Treat (ITT) analysis, we found effects for the intervention on teachers' implementation of high-impact instructional strategies and students' language and literacy skills. [This article was published in "American Educational Research Journal" (EJ1167074).]