Abstract Background Childhood hearing loss (HL) predicts poor mental health and is associated with a higher risk of communication difficulties. The relationship of childhood HL with specific types of poor mental health (such as depressive symptoms or self-harm) and peer victimisation remains unclear. Methods We analysed data from the Millennium Cohort Study (MCS), a prospective observational cohort study of children living in the UK at age 9 months and born between 2000 to 2002. Data were available on the children and their families at ages 9 months, then at 3, 5, 7, 11, and 14 years. Participants were 10,858 singleton children with self-reported data on peer victimisation, depressive symptoms, and self-harm at age 14 years. Multivariable logistic regression models were fitted to estimate odds ratios (OR) for HL with peer victimisation, depressive symptoms, and self-harm. HL presence was examined in terms of any HL between ages 9 months and 14 years, as well as by HL trajectory type (defined by onset and persistence). Analyses were adjusted for potential sources of confounding, survey design, and attrition at age 14 years. Interactions between sex and HL were examined in each model and multiple imputation procedures used to address missing data. Results Children with any HL had increased odds of depressive symptoms (OR: 1.32, 95% CI: 1.09–1.60), self-harm (1.41, 1.12–1.78) and, in girls only, peer victimisation (girls: 1.81, 1.29–2.55; boys: 1.05, 0.73–1.51), compared to those without HL. HL with later age at onset and persistence to age 14 years was the only trajectory associated with all outcomes. Conclusions Childhood HL may predict peer victimisation (in girls), depressive symptoms, and self-harm. Further research is needed to identify HL trajectories and methods to facilitate good mental health in children with HL.