In this study, we examined whether sociolinguistic awareness and false belief were uniquely related in 3- and 4-year-old Cantonese-speaking children learning English as a second language. The English-use background of these children varied so that they possessed sociolinguistic awareness to different degrees. Results indicated that sociolinguistic awareness predicted false belief uniquely after controlling for age, nonverbal intelligence, English vocabulary, and family income for both the second language learners and the more balanced bilinguals. The group difference in false belief was adequately explained by the corresponding difference in sociolinguistic awareness over and above the other variables. Such findings provide evidence for the claim that false belief understanding is critically related to sociolinguistic awareness, which in turn is influenced by how a second language is learned. (Contains 2 tables.)