The article reviews the development and significance of emotion-related self-regulation in children, focusing on the distinction between effortful and less voluntary self-regulatory processes. It highlights that emotion-related self-regulation develops rapidly in early life and improves more slowly into adulthood, with individual differences in self-regulation being relatively stable after the first year or two of life. These differences are inversely related to externalizing problems but show less consistency in relation to internalizing problems. The article discusses the role of genetic and environmental factors in shaping self-regulatory capacities and the effectiveness of interventions aimed at fostering self-regulation to reduce maladjustment. It also explores the conceptual issues surrounding emotion regulation, including the differentiation between voluntary and involuntary control processes, and the development of effortful control from infancy through adolescence. The stability of effortful control over time is examined, along with its relations to both externalizing and internalizing problems. The article concludes by discussing the complex interplay between self-regulation and physiological measures, such as cardiac vagal regulation, in predicting maladjustment.The article reviews the development and significance of emotion-related self-regulation in children, focusing on the distinction between effortful and less voluntary self-regulatory processes. It highlights that emotion-related self-regulation develops rapidly in early life and improves more slowly into adulthood, with individual differences in self-regulation being relatively stable after the first year or two of life. These differences are inversely related to externalizing problems but show less consistency in relation to internalizing problems. The article discusses the role of genetic and environmental factors in shaping self-regulatory capacities and the effectiveness of interventions aimed at fostering self-regulation to reduce maladjustment. It also explores the conceptual issues surrounding emotion regulation, including the differentiation between voluntary and involuntary control processes, and the development of effortful control from infancy through adolescence. The stability of effortful control over time is examined, along with its relations to both externalizing and internalizing problems. The article concludes by discussing the complex interplay between self-regulation and physiological measures, such as cardiac vagal regulation, in predicting maladjustment.