OBJECTIVES: This study investigates the relationship between emotional symptoms and dental caries in adolescents and the role of dietary patterns as mediating variables. METHODS: This cross-sectional study used a multistage stratified random sample of schools, in Jiangsu, with a sample of 17,997 adolescents aged 11-19. Measures included emotional symptoms, dental caries, toothbrushing frequency, and dietary patterns. Logistic and Poisson regression models were conducted to test mediation hypotheses. RESULTS: The decayed, missing, and filled teeth index (DMFT) was related to depressive symptoms following adjustment for other variables (incidence rate ratios [IRR] = 1.09; p < 0.05), but not to anxiety symptoms level (IRR = 1.02; p > 0.05). The link between depressive symptoms and DMFT had a partial mediation impact on toothbrushing frequency (a, b, c' all p < 0.05). Sugary foods, but not fried foods, partially mediated the link between depressive symptoms and caries when toothbrushing frequency was adjusted. CONCLUSION: There are direct and indirect associations between emotional symptoms and caries; the latter may be due to changes in oral health behaviours that increase the risk of caries.