This is the first study to examine dual language and socioeconomic status (SES) differences in both structural brain and cognitive development in a sample of 562 participants (281 monolingual users and 281 dual-language users) ages 3-20 years. Bilingualism has been associated with different patterns of brain development than monolingualism, and some studies have even reported differences between bilinguals and monolinguals on aspects of cognitive development. SES has been linked to both brain development and cognitive skills, with lower socioeconomic status posing risks to early learning. The current study finds that dual language exposure may lead to differences in brain structure, even when considering SES, with dual-language exposure possibly buffering the effects of SES on the brain during adolescence. As with all scientific studies, more research needs to be conducted to understand how early experiences can shape brain and behavior.