Students who speak English as a second language (ESL) face considerable challenges in English language universities, but little is known about the relationship between English-language acculturation and academic performance. A prospective, correlational design was used to validate the English Language Acculturation Scale (ELAS), a measure of the linguistic aspect of acculturation, and to determine the relationship between English-language acculturation and academic achievement among 273 first-year nursing students. Exploratory factor analyses demonstrated that the ELAS was a valid and reliable measure (#=.89). When E LAS scores were examined in relation to students' grades, students with the lowest ELAS scores also had the lowest mean subject grades, highlighting the need to place greater emphasis on identifying English-language acculturation among ESL students. �� 2007 Wiley Periodicals, Inc.