The present study evaluates the role of age on the rate of acquiring English as a second language in an immersion setting. Subjects were children with native languages typologically very different from English. The children arrived in the United States between the ages of 7 and 12 years and were tested on their knowledge of English grammatical morphology and syntax at different lengths of stay in the United States, ranging from 6 months to 3 years. Subjects' performance was predicted by the length of their stay in the United States and by gender, with females outperforming males. Age of arrival played no role in predicting subjects' rate of acquisition. Performance was very similar between two age groups examined (7–9– and 10–12-year-old arrivals) throughout the 3 years measured. The present results suggest that, on certain aspects of grammar, different-aged children acquire a second language during the first 3 years of acquisition at similar rates when their native language is very different in typology from the target language.