High levels of stress, anxiety and depression have been reported in patients with orofacial pain. Dental pain has the potential to reduce quality of life (QOL), and pain relief is important aspect of QOL. The purpose of this study was to assess the relationships of dental pain with QOL and mental health using a nationally representative, population-based study. This study analyzed data from the 2012 Korea National Health and Nutrition Examination Survey (N = 5469). Oral health status was assessed using the oral health questionnaire, and oral examination was performed by trained dentists. Health-related QOL (HRQOL) was evaluated using EQ-5D and EQ-VAS, and mental health was evaluated by questionnaires. Logistic regression was applied to estimate adjusted odds ratios (AOR) and 95% confidence intervals (CI). Among 5469 adults, 1992 (36.42%) presented self-reported dental pain. Participants with anxiety/depression or pain/discomfort, and participants with stress, melancholy, suicidal thought or depression showed significantly higher prevalence of dental pain. After adjusting for covariates, five aspects of QOL and five aspects of mental health were related with dental pain. The AORs (95% CI) for dental pain were 1.39 (1.06–1.81) for mobility, 1.77 (1.19–2.63) for self-care, 1.38 (1.02–1.85) for usual activities, 1.73 (1.43–2.09) for pain/discomfort and 1.50 (1.13–1.98) for anxiety/depression. For mental health status factors, the AORs (95% CI) for dental pain were 1.29 (1.11–1.51) for stress, 1.37 (1.09–1.74) for melancholy, 1.26 (1.01–1.58) for suicidal thoughts, 1.43 (.93–2.19) for consultation to psychiatrist and 1.53 (1.07–2.19) for depression. This study showed that dental pain has an association with lower HRQOL and worse mental health status in South Korean adults.