This workshop brought together scientists with expertise in pediatric obesity, epidemiology, developmental psychology, developmental and behavioral pediatrics, nutrition, physical activity, sleep, temperament, and parenting to determine: (1) what is known regarding risk for excess weight gain in infancy and early childhood; (2) what is known regarding interventions that are promising or have been shown to be efficacious; and (3) challenges and opportunities in implementing and evaluating behavioral interventions in parents and other caregivers and their young children. The goal of the workshop was to provide the scientific background to inform research that will develop and test interventions to prevent inappropriate weight gain during infancy and early childhood, with a goal of increasing the proportion of children who enter school age at a healthy weight.