Sociomoral development reflects children’s social understanding of sociomoral events, which are events that focus on the prescriptive limits of interpersonal behavior, such as events involving the victimization of others or the following of social conventions. Research shows that children can distinguish between events that are straightforward social conventional and events that are straightforward moral. In early childhood, however, children have trouble coordinating events that involve multiple competing factors such as when conventions might compete with moral principles. This entry provides an overview of social development theory that drives research on sociomoral development in early childhood, and it reviews research findings documenting judgments and reasoning about sociomoral events, as well as the implications for this research in promoting sociomoral development in early childhood classrooms.