Purpose: To assess any clustering between obesity, dental health, and lifestyle factors (dietary patterns, physical activity, smoking, and alcohol consumption) among adolescents. Material and Methods: A cluster sample of 15-year-old Danish adolescents (DA) from eight municipalities was selected. Self-reported questionnaires for adolescents and their mothers to assess body-mass index (BMI), socioeconomic and lifestyle factors, and clinical examinations to examine adolescents' dental status (DMFT) were used. Descriptive statistics, chi-square tests, and factor analysis were applied. Results: The mean DMFT was 2.03 and mean BMI was 21.30 among DA.Of the whole sample, 62% experienced caries (DMFT > 0) and 16% were classified as obese. No association appeared between obesity and DMFT (p > 0.05). Most adolescents were likely to have breakfast every day (76%), but their daily consumption of fruit was lower (38%). More than half of adolescents reported having physical exercise (66%) and no alcohol consumption (57%). Smokers were more likely to consume alcohol (80%) but less likely to exercise (44%) than nonsmokers (alcohol consumption, 55%; exercise, 68%), (P 0.05). Principal component analysis revealed that DMFT and obesity were interrelated in DA. Conclusion: In line with earlier studies, obesity and dental caries share common lifestyle factors among adolescents, regardless of nationality and different health-care systems. Thus, it seems that dental health is a global health concern. There is a need for collaboration between dental and general health-care providers to manage both obesity and dental caries in adolescents by using a holistic approach. Keywords: obesity, dental caries, lifestyle, adolescents