OBJECTIVE: To explore the associations between probable developmental coordination disorder (DCD) defined at age 7 years and mental health difficulties at age 9 to 10 years. METHODS: We analyzed of prospectively collected data (N = 6902) from the Avon Longitudinal Study of Parents and Children. "Probable" DCD was defined by using Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision criteria as those children below the 15th centile of the Avon Longitudinal Study of Parents and Children Coordination Test, with functional limitations in activities of daily living or handwriting, excluding children with neurologic difficulties or an IQ <70. Mental health was measured by using the child-reported Short Moods and Feelings Questionnaire and the parent-reported Strengths and Difficulties Questionnaire. Multiple logistic regression models, with the use of multiple imputation to account for missing data, assessed the associations between probable DCD and mental health difficulties. Adjustments were made for environmental confounding factors, and potential mediating factors such as verbal IQ, associated developmental traits, bullying, self-esteem, and friendships. RESULTS: Children with probable DCD (N = 346) had an increased odds of self-reported depression, odds ratio: 2.08 (95% confidence interval: 1.36-3.19) and parent-reported mental health difficulties odds ratio: 4.23 (95% confidence interval: 3.10-5.77). The odds of mental health difficulties significantly decreased after accounting for verbal IQ, social communication, bullying, and self-esteem. CONCLUSIONS: Children with probable DCD had an increased risk of mental health difficulties that, in part, were mediated through associated developmental difficulties, low verbal IQ, poor self-esteem, and bullying. Prevention and treatment of mental health difficulties should be a key element of intervention for children with DCD.