Purpose: Growing evidence associates low oral health literacy (OHL) with poor oral health outcomes. While nearly half of United States adults have periodontal disease (PD), there are conflicting results on association between OHL and PD. The purpose of this pilot study was to explore the association between functional OHL and periodontal health as defined by the American Academy of Periodontology (AAP) classification system.Methods: A cross-sectional study was conducted with a convenience sample of dental patients presenting for care at a Midwestern Federally Qualified Health Center. Functional OHL was measured using the Oral Health Literacy Adults Questionnaire (OHL-AQ), and periodontal health was measured clinically and categorized by stage and grade using the recently revised AAP classification system. Additional demographic factors and health history information related to periodontal health were collected. Descriptive analysis reported the median and range for ordered variables, and frequency and percentages for categorical variables. Wilcoxon rank sum test, Kruskal-Wallis test, and Spearman correlation coefficients were used to find association between functional OHL and periodontal health.Results: Among fifty-four participants, statistically significant associations were found between OHL-AQ scores and AAP staging and grading categories. Periodontal disease stage increased with age, and periodontal disease grades progressed among participants with diabetes. No associations were found between periodontal health and sex, race, ethnicity, education, insurance, or country of origin.Conclusion: Functional oral health literacy had a significant inverse relationship with both AAP periodontal disease staging and grading. A larger study is needed to confirm the findings of this pilot study.