BackgroundIt is known that sleep problems impact children’s health, learning, and school performance. The purpose of this paper is to examine the association between sleeping habits and social competence development.MethodsThree hundred and nine caregiver-child dyads participated in this study, which was conducted as part of a Japan Science and Technology Agency (JST) project. The caregivers answered some questionnaires about sleeping habits when the child was 9 months and 18 months old. Caregiver-child interaction was observed when the child was 30 months old, and the features of the interaction were examined using the Interaction Rating Scale (IRS) as a measure of social competence.ResultsThe caregivers’ attitude toward sleeping in the 9-month period was found to be significantly correlated with the children’s social competence at 30 months. Moreover the caregivers’ attitude toward sleeping in the 9-month period significantly correlated with the children’s sleeping habits at 9 and 18 months.ConclusionsThese findings show that the caregivers’ attitude toward sleeping is an important factor influencing the development of children’s social competence.