BACKGROUND: Secondhand Smoking (SHS) has been suggested as a major health problem in the world and is known to cause various negative health effects that have in turn caused the deaths of almost 600,000 people per year. Evidence has suggested that SHS may have an effect on health problems and such findings have influenced the implementation of smoking-free areas. However, few studies have investigated the effects of SHS on stress which is considered major risk factor for mental health. Thus, the purpose of our study was to investigate the association between exposure to SHS and stress. METHODS: We performed a cross-sectional study using data from the Korea National Health and Nutrition Examination Survey (2007-2012). In our study, a total of 33,728 participants were included to evaluate the association between SHS exposure and stress based on smoking status. Association between SHS exposure and stress was examined using logistic regression models. RESULTS: A total of 12,441 participants (42.9 %) were exposed to SHS in the workplace or at home. In our study, exposure to SHS was significantly associated with higher stress compared to non-exposure, regardless of smoking status (smoker odds ratio [OR]: 1.22; ex-smoker OR: 1.25; never-smoker OR: 1.42). Our results showed that the effect of SHS on stress was greater when exposure took place both at home and in the workplace in smokers and never-smokers. CONCLUSIONS: Exposure to SHS in the workplace and at home is considered to be a risk factor for high stress in both smokers and never-smoker. Therefore, strict regulations banning smoke which can smoking ban reduce SHS exposure are recommended in order to improve the populations' health.