The ABCD Data Repository houses all data generated by the Adolescent Brain Cognitive Development (ABCD) Study. The ABCD Study is a landmark, longitudinal study of brain development and child health. Investigators at 21 sites around the country will measure brain maturation in the context of social, emotional and cognitive development, as well as a variety of health and environmental outcomes. For more information about the ABCD Study, please visit the ABCD Study website. The ABCD Study is supported by NIH partners (the National Institute on Drug Abuse, the National Institute on Alcohol Abuse and Alcoholism, the National Cancer Institute, the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the National Institute of Mental Health, the National Institute on Minority Health and Health Disparities, the National Institute of Neurological Disorders and Stroke, the National Heart, Lung, and Blood Institute, the NIH Office of Behavioral and Social Sciences Research, and the NIH Office of Research on Women’s Health), as well as the Centers for Disease Control and Prevention – Division of Adolescent and School Health.  This repository will store data generated by ABCD investigators, serve as a collaborative platform for harmonizing these data, and share those data with qualified researchers.