Although better diet quality is inversely related to the risk of geriatric disorders, the association of adherence to dietary guidelines with oral health-related quality of life (OHRQoL) is unclear. We aimed to investigate this association in older Japanese adults. This cross-sectional study included 7,984 Japanese participants aged ≥65 years from the population-based Kyoto-Kameoka study. Dietary intake was estimated using a validated self-administered food frequency questionnaire. The scores for adherence to the Japanese Food Guide Spinning Top (range: 0 [worst] to 80 [best]) were calculated. These scores were stratified into quartiles (Qs). Poor OHRQoL was defined as a score ≤ 50 using a 12-item Geriatric Oral Health Assessment Index. The odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using multivariable logistic regression and the spline model. Higher adherence score was associated with a lower prevalence of poor OHRQoL (Q1-Q4: 36.0%, 32.1%, 27.9%, and 25.1%, respectively). An inverse association was found between the score for adherence to the food-based Japanese dietary guidelines and the ORs of poor OHRQoL among all the participants (Q1: reference; Q2: OR, 0.87 [95% CI: 0.75-1.00]; Q3: OR, 0.77 [95% CI: 0.66-0.90]; Q4: OR, 0.72 [95% CI: 0.62-0.85]; p for trend < 0.001). These relationships were similar to the results in the spline model. Higher adherence to the food-based Japanese dietary guidelines is inversely associated with the prevalence of poor OHRQoL in older adults. Our results may provide useful insights to improve and maintain oral health.