The number of immigrant children in the US continues to grow rapidly, but pediatric immigrant health remains a poorly understood domain. Previous research suggests immigrant children have reduced risk for injury, but the reason for that finding remains unknown. One leading hypothesis is cultural—less acculturated children in the United States appear to be protected from injury—but the combined influence of immigrant status and acculturation is unclear. This study examines the roles of immigration and language acculturation on pediatric injury risk. Samples of 8,526 children and 4,010 adolescents included in the 2003 California Health Interview Survey were studied. The primary analytic technique was Poisson regressions predicting incidents of injury requiring professional medical attention. Predictor variables included demographic characteristics, health insurance availability, birthplace (US vs. other), and language acculturation. Both birthplace and language acculturation were related to children's and to adolescent's risk for unintentional injury, but language acculturation emerged as the stronger univariate predictor and only multivariate predictor of injury in both models. Possible interpretations of the results are discussed.