The number of U.S. children living in households with extended families has greatly increased in the last 4 decades. This demographic shift calls for a reevaluation of the impact of household size on children's development. Household density (HHD), measured as the ratio of people to bedrooms in a home, has been shown to negatively relate to children's language. Here, we propose that while greater HHD may result in poorer language abilities, more adults in relation to the number of children in the home may have a positive impact on children's language. To test this hypothesis, we studied relations between HHD and adult-to-child ratio with children's vocabulary scores, as well as whether maternal education and household chaos accounted for these associations. Participants included families from a range of socioeconomic and ethnic backgrounds (N = 275; M[subscript age] = 10.85; 51% female; 51% Hispanic; annual income range less than $10,000-over $100,000). In general, higher HHD was related to lower child vocabulary scores. Conversely, higher adult-to-child ratio was related to higher child vocabulary and lower household chaos. These patterns were primarily driven by effects in Hispanic families. Our results suggest that a reevaluation of household size is needed, as more adults in the home can be protective for children's language development in larger families, an effect that may vary by culture.