An important subgroup of English learner-classified (EL) students immigrate to the U.S., entering U.S. schools upon their arrival. Using growth models and statewide data, this study describes the incoming English proficiency and subsequent English language growth of newcomer students, including the student, program, and school characteristics that are associated with differences in English language growth patterns among newcomers. The study further explores how newcomer students' English proficiency levels and growth compare to those of their non-newcomer EL-classified peers. We find that, on average, newcomer students have low initial English proficiency levels, but their English proficiency develops quickly. There is wide variation in newcomer English level and growth patterns, however, suggestive that schools play an important role in fostering growth. Finally, we find exploratory evidence that newcomers enter school at earlier stages of English proficiency compared to their non-newcomer peers, but grow faster, especially in their first two years. [This paper was published in "Bilingual Research Journal" v45 n2 p180-204 2022.]