OBJECTIVE: This prospective study investigated the cross-sectional association between impaired oral health-related quality of life (OHRQoL) and the prevalence of depressive symptoms, and the longitudinal association between impaired OHRQoL and development of depressive symptoms among older adults. BACKGROUND: Previous studies have shown a relationship between poor oral health and depression among older adults; however, findings are inconsistent. MATERIALS AND METHODS: Participants were 669 community-dwelling older Japanese individuals aged≥55 years (mean: 67.8 ± 7.2 years). Data of 296 participants were used for longitudinal analyses. OHRQoL was evaluated using the Oral Impacts on Daily Performances scale. Impaired OHRQoL was defined as the presence of at least one impact on the scale. Depressive symptoms were assessed using the Japanese version of the Zung self-rating depression scale with a cut-off score of 40. RESULTS: The cross-sectional logistic regression model demonstrated that impaired OHRQoL was significantly associated with depressive symptoms (odds ratio [OR], 5.17; 95% confidence interval [CI], 2.99-8.95) independent of age, sex, body mass index, hypertension, cerebrovascular/cardiovascular disease, smoking, drinking alcohol, education, cognitive function, objective oral health (dentition status) and oral health behaviour (dental visit within 1 year). Similarly, impaired OHRQoL predicted the development of depressive symptoms within 4 years in a fully adjusted longitudinal model (OR, 6.00; 95% CI, 1.38-26.09). CONCLUSION: Impaired OHRQoL was identified as a potential comorbidity of depressive symptoms and a predictor for depressive disorder later in life. OHRQoL may be a useful clinical outcome for elder patients with regard to their mental and oral health.