<p><b>AIM: </b>We investigated the cross-sectional association between diet quality and severe periodontitis in a sample of diverse Hispanics from the Hispanic Community Health Study/Study of Latinos.</p><p><b>MATERIALS AND METHODS: </b>A total of 13,920 Hispanic/Latinos aged 18-74 years of different heritages underwent a full-mouth oral examination and completed two 24-hr dietary recalls during 2008-2011. Severe periodontitis was defined as having ≥30% tooth sites with clinical attachment loss ≥5 mm. Diet quality was assessed using the Alternative Healthy Eating Index (AHEI-2010). We evaluated the association of diet quality with severe periodontitis adjusting for age, sex, nativity status, income, education, last dental visit, current insurance, cigarette smoking, diabetes, and energy intake.</p><p><b>RESULTS: </b>Relative to those at the lowest quartile of diet quality, individuals at the highest quartile had significantly lower odds of severe periodontitis (adjusted OR = 0.57, 95% CI: 0.39-0.82), with evidence of a dose-response relationship across AHEI quartiles. Among AHEI-2010 components, higher consumption of whole grains and fruits, and lower consumption of red/processed meats were associated with lower odds of severe periodontitis.</p><p><b>CONCLUSION: </b>Better-quality diet was associated with lower prevalence of severe periodontitis although the causal pathways need to be clarified in future work.</p>