Abstract Research on heritage language development in children can profit greatly by incorporating insights from analyses of structured variation , which is defined as the interchange of linguistic forms where the choice to use one form over the other is probabilistically conditioned by linguistic and social factors. This article reviews the limited research on bilingual children's structured variation, focussing specifically on child heritage speakers of Spanish. It is argued that careful attention to structured variation advances our understanding of heritage language development in childhood and can help us move beyond a deficit view of bilingualism.