Objectives: This study aimed to identify the socioeconomic factors related to tooth brushing behavior among adults in Korea. Methods: This cross-sectional study used data from the Korea Community Health Survey (KCHS) in 2019. Respondents aged 19 years and older (n=299,099) comprised the study sample. The dependent variable was tooth brushing behavior, whereas the independent variables were demographic and socioeconomic factors. The data were processed using chi-squared test, independent t-test, ANOVA, and adjusted multiple logistic regression analysis were performed. Statistical analysis was performed using the STATA 17.0 program, with significance set at the 5% level. Results: About half (55%) of the respondents brushed their teeth at least twice a day. The findings also revealed significant differences according to socioeconomic status (P<.01). Those who brushed their teeth less than twice a day had the following characteristics: men, aged 45 years or older, low income, working outside, less educated, without a spouse, and living in rural areas. Adjusted multiple logistic regression analysis showed that the area of residence contributed to tooth brushing behavior. Conclusions: The area of residence, as well as socioeconomic status, should be considered in oral health education and intervention strategies.