Teachers Educating All Multilingual Students (TEAMS) is a teacher professional development program at Oregon State University that culminates in an English for speakers of other languages endorsement and/or a dual language specialization. TEAMS is partially funded through an Office of English Language Acquisition National Professional Development grant from the U.S. Department of Education, and participants receive scholarships to cover tuition. This study explores whether TEAMS professional development had an impact on the academic outcomes of English learner students whose teachers participated in TEAMS. The study authors used a two-step matching procedure to identify a group of comparison teachers in TEAMS school districts who appeared likely to enroll in TEAMS. They then selected a subset of students who had statistically indistinguishable demographic characteristics, program enrollment, and academic achievement from TEAMS students. Due to complications related to the COVID-19 pandemic, reliable assessment data were only available for the academic year 2018/19. The study found that teachers' participation in TEAMS positively impacted English learner students' English language arts assessment outcomes. English language arts testing scores of English learner students taught by TEAMS teachers were 0.348 standard deviations higher than those of comparison students taught by comparison teachers. This difference is statistically significant and of moderate size, representing a 13.6 percentile point increase for an average English learner student. Teachers' participation in TEAMS had no impact on students' English language proficiency outcomes.