Internationally adopted (IA) children have often experienced early adversity and are at risk for long-term deficiencies in multiple developmental domains. This study examined the association between IA children's joint attention (JA) soon after arrival and later cognitive, communicative, and socioemotional competency 6 months' postadoption. We expected a child's initial JA would positively predict later cognitive, communication, and social ability. IA children (n = 63) adopted from Eastern Europe were seen soon after their arrival into the United States to assess their JA. Their socioemotional competency, social communication, and cognitive abilities were measured at a follow-up session 6 months' postadoption. We found that higher order JA was positively associated with measures of social relatedness. Furthermore, individual hierarchical regressions of each measure of JA (higher order JA, initiating JA, responding to JA, and initiating behavior requests [BR]) considered with age-at-adoption showed that each measure was an independent and positive predictor of Mullen outcomes in the receptive and expressive language domains. These results suggest that JA may be a sensitive predictor of subsequent functioning in the social, communicative, and cognitive domains. Thus, assessing JA soon after arrival has the potential to identify at-risk IA children, and interventions targeting JA may support those children in overcoming the negative impacts of early adversity.