Purpose This study aimed to investigate the relationship between smoking and subjective sleep quality in the Korean adult population. Methods We designed a cross-sectional survey using data from the 2018 Korean Community Health Service Conditions Survey and selected smoking status as our variable of interest. We divided the participants into people who currently, never, and formerly smoked, those who smoked < 20 cigarettes/day, and those who smoked > 20 cigarettes/day. Subjective sleep quality was analyzed using the Pittsburgh Sleep Quality Index. Multiple logistic regression analysis was performed for statistical analysis. Results A total of 174,665 participants were enrolled. People who formerly and currently smoked were found to have poorer subjective sleep quality than those who never smoked. The odds of poor subjective sleep quality in people who smoked > 20 cigarettes/day were 1.15 times (95% confidence interval: 1.09-1.21) for men and 1.51 times (95% confidence interval: 1.22-1.86) for women, compared with men and women who never smoked. Conclusions Smoking was negatively associated with subjective sleep quality. Smoking cessation programs and lifestyle improvement education may be justifiable to improve the quality of sleep in Korean adults.