This study describes the development of emotional and behavioral regulation in a regional cohort of children born extremely preterm (less than 28 weeks gestational age, n = 39), very preterm (less than 34 weeks gestational age, n = 56), and full term (n = 103). At 2 and 4 years, children born at younger gestational ages demonstrated poorer self-regulation across multiple contexts spanning observed interactions, formal cognitive testing, and parental report of child behavior at home. Among children born preterm, the 2 strongest predictors of impairments in self-regulation were the presence of moderate-to-severe cerebral white matter abnormalities on neonatal magnetic resonance and a less sensitive parenting style when children were aged 2 years. Findings support the importance of early neurological development and parenting for developing regulation in children born very preterm.