Sleep problems are known to be risk factors for subsequent emotional and behavioral difficulties in childhood and adolescence. To date, there has been no study investigating the relationships between sleep habits and behavioral problems in a large nonclinical sample of preschool age children. The aim of this study was to examine these relationships and factors associated with the sleep habits of preschool age (2 to 5 year old) children. Their mothers (n = 1,746) completed a multiple-choice questionnaire about the sleep habits and behavior problems of their children, as well as their own sleep habits and working hours at Tokyo metropolitan public nursery schools. The short sleep duration group showed significantly higher aggressive scores than the long sleep duration group among 2- to 3-year-old children, and the irregular bedtime group showed significantly higher aggressive and attention problem scores than the regular bedtime group among 4- to 5-year-old children. Univariate and multivariate logistic regression analyses revealed that children's late bedtime was associated with their mother's late waking-up time, and late schedule of both the mother's leaving and returning home. This study recognized an association between behavioral problems and poor sleep habits among preschool-age children. It is important for children to sleep regularly and adequately in order to decrease their behavior problems. In conclusion, appropriate management of children's sleep by their mothers is necessary for promoting sleep-related health of children.