BACKGROUND Difficulties in fine and gross motor skills are often overlooked as developmental problems, although approximately 6-13% of all school-age children have poor motor coordination. Understanding motor coordination is important from the perspective of school adaptation. This longitudinal cohort study aimed to determine whether fine and gross motor skills in preschool children predict later academic achievement and psychosocial maladaptation. METHODS Participants were 2,501 children from nursery and elementary schools (5-13 years old). The motor skills of preschool children were assessed by their nursery teacher immediately before entering elementary school. The Strengths and Difficulties Questionnaire and a standardized Japanese test were administered annually throughout elementary school. RESULTS Early motor difficulties in preschool children had significant effects on their academic achievement and psychosocial maladaptation up until the sixth grade. Gross motor difficulties in preschool were associated with the later peer problems and worsened emotional symptoms. CONCLUSIONS Motor skills in preschool children are useful as a predictor of later psychosocial maladaptation and academic achievement.