To identify the relationship between periodontal health knowledge and oral health-related quality of life among Caribbean adults. A cross-sectional study was conducted in a representative sample from 3 Caribbean cities (weighted N = 1805). Participants completed a questionnaire on oral health knowledge, hygiene habits, and other practices, as well as the Oral Health Impact Profile-14 (OHIP-14) questionnaire. The associations between knowledge and habits and OHIP-14 score and its tertiles were evaluated using negative binomial and multinomial logistic regression models, respectively, adjusting for confounders. Odds ratios and regression coefficients were reported. Participants reporting none, little, and adequate knowledge about gum health had higher odds of being in the worst tertile for OHRQoL, compared to those reporting "good knowledge" (ORnone vs good = 2.38, 95% CI: 1.59-3.54; ORlittle vs good = 1.82, 95% CI: 1.19-2.78; ORadequate vs good = 1.68, 95% CI: 1.11-2.57). Participants reporting toothbrushing ≥ twice/day were less likely to be in the worst tertile for OHRQoL, compared to those brushing less often (OR = 0.67, 95% CI: 0.48-0.92). Self-reported gum bleeding was associated with double the odds of being in the worse tertile (OR = 2.03, 95% CI: 1.60-2.58). According to the findings of this study, periodontal health knowledge is associated with reduced OHRQoL in Caribbean Adults. In addition, the frequency of brushing and the self-reported gum bleeding was related to a worse quality of life (QoL) level.