Objectives: To explore the association between oral hygiene status and obesity among preschool children in Hong Kong. Methods: Three hundred and twenty-four 5-year-old children in Hong Kong were recruited. Their oral hygiene status was recorded using visible plaque index (VPI). Body height, body weight, waist circumference (WC), hip circumference and triceps skinfold thickness (TRSKF) were measured to assess general adiposity (weight/height ratio, W/H; body mass index, BMI), central adiposity (WC; waist/hip ratio, WHR) and peripheral adiposity (TRSKF). The relationships between VPI and W/H, BMI, WC, WHR and TRSKF were examined in bivariate and regression analyses. Results: Fifty-six per cent of the children were considered to have high VPI (VPI ≥ 65.0%). Logistic regression analyses identified that W/H z-score (OR = 1.28, 95% CI = 1.01-1.61) and WC z-score (OR = 1.25, 95% CI = 1.00-1.58) were associated with high VPI. No association was found after adjusted for socio-demographic status (P > 0.05). Conclusion: Oral hygiene status was not associated with obesity among 5-year-old children in Hong Kong after controlling for socio-demographic factors. © 2013 John Wiley & Sons A/S.