OBJECTIVES: Children born very preterm (VPT) are at an increased risk of developing mental health (MH) disorders. Our aim for this study was to assess rates of MH disorders in children born VPT and term at 13 years of age and stability of MH disorders between ages 7 and 13 years by using a diagnostic measure. METHODS: Participants were from the Victorian Infant Brain Study longitudinal cohort and included 125 children born VPT (<30 weeks’ gestational age and/or <1250 g) and 49 children born term (≥37 weeks’ gestational age) and their families. Participants were followed-up at both 7 and 13 years, and the Development and Well-Being Assessment was administered to assess for MH disorders. RESULTS: Compared with term peers, 13-year-olds born VPT were more likely to meet criteria for any MH disorder (odds ratio 5.9; 95% confidence interval 1.71–20.03). Anxiety was the most common disorder in both groups (VPT = 14%; term = 4%), whereas attention-deficit/hyperactivity disorder carried the greatest differential elevated risk (odds ratio 5.6; 95% confidence interval 0.71–43.80). Overall rates of MH disorders remained stable between 7 and 13 years, although at an individual level, many participants shifted in or out of diagnostic categories over time. CONCLUSIONS: Children born VPT show higher rates of MH disorders than their term peers, with changing trajectories over time. Findings highlight the importance of early identification and ongoing assessment to support those with MH disorders in this population.