This study examines vocabulary growth rates in first and second languages for Spanish-speaking and Cantonese-speaking English language learners from kindergarten through second grade. Growth-modeling results show a within-language effect of concepts about print on vocabulary. Language exposure also had an effect on English vocabulary: earlier English exposure led to larger English vocabulary in kindergarten. There was no interference of early English exposure on native-language vocabulary. Moreover, Cantonese-speaking children had higher English expressive vocabulary scores than Spanish-speaking children and this difference remained for the 3 years. In contrast, although there were no significant differences in first language vocabulary at the start of kindergarten, Spanish-speaking children had steeper growth rates in first-language vocabulary than Cantonese-speaking children, after controlling for language of instruction and first-language concepts about print.