Purpose: To evaluate the relationship between decayed, missing and filled teeth (DMFT index) and body mass index (BMI) in a Turkish population of adults aged 20–30 years who did not have any chronic diseases. Materials and Methods: This study was conducted on a total of 394 patients. DMFT index was used to define the number of teeth with decays, teeth with fillings, and missing teeth. The body weight and height of the study participants were measured with a digital scale and height rod. BMI was calculated by dividing the body weight by the square root of the height. One-way analysis of variance (ANOVA) and Bonferroni tests were used to compare three or more groups and to compare two groups, respectively. The statistical significance level was evaluated at p < 0.05. Results: Differences in DMFT index among BMI groups was found to be statistically significant (p = 0.001; p < 0.01). DMFT index was significantly higher in the obese group than in the normal-weight group (p = 0.001) and overweight group (p = 0.001). No statistically significant differences were found between DMFT indices of study participants of normal weight and those who were overweight (p > 0.05). Conclusion: Positive correlation was observed between obesity and DMFT index. Coadministration of obesity prevention programmes and preventive oral health programmes can improve public health to a better point.