jats:pRecently, empirical studies have indicated an association between well-being and mental health. The nature of this association remains unclear since some studies suggest it is weak, whilst others indicate it is strong. The present study seeks to contribute to this dialogue by modelling not only the relationship between well-being and internalising and externalising mental health symptoms but also by introducing a mediation model where school and sibling bullying, as risk factors, are acting as mediators. A national sample of 1244 youth (Mage = 12.47, SD = 1.69) from the Understanding Society household panel study in the UK was utilised to estimate the structural equation model. The findings showed that the direct effect of well-being on internalising symptoms was negative and strong, whereas it was negative and moderate on externalising symptoms. Furthermore, the pattern of indirect effects from subjective well-being to internalising and externalising mental health symptoms displayed some differences in the level of statistical significance and strength. Implications for policy and practice are discussed.</jats:p>