Whereas previous research has examined the role that parenting and home environments play in explaining the relation between family socioeconomic status and children's language development in the United States, relatively little is known about the associations between these constructs in other cultures. This study tested an integrated model of language development within a longitudinal data set of 1,894 socioeconomically diverse Korean children (48.35% girls; > 99% native-born Korean citizens) from the first year of life (age 3-8 months) to ages 3 and 6 years. A model integrating parent and environmental characteristics from the family stress model and the family investment model that also included maternal self-efficacy and knowledge of child development was shown to adequately explain the associations between family socioeconomic status and children's language development. Implications for applying similar integrated models in international contexts are discussed.