Smokers are at high risk of oral disease and report sub-optimal oral hygiene. Improving smokers’ oral hygiene could reduce their future disease risk. The purpose of this study is to assess the effects of a novel, multi-modal oral health promotion program (Oral Health 4 Life; OH4L) targeted to socioeconomically disadvantaged smokers and delivered through state-funded tobacco quitlines. Smokers (n = 718) were randomized to standard quitline care or standard care plus OH4L. OH4L recipients received a comprehensive behavioral intervention and were advised of the benefits of routine oral hygiene, encouraged to brush and floss daily (for better oral health and to manage cigarette cravings), and provided a toothbrush and floss. Participants were followed for 6 months to assess the intervention effects on routine oral hygiene (brushing and flossing) and changes in motivation and self-efficacy. Data were collected between 2015 and 2017. At 2-month follow-up, OH4L participants were more likely to meet the American Dental Association (ADA) recommendations for brushing twice daily (adjusted RR = 1.15 [1.04, 1.27], p = .006), flossing daily (adjusted RR = 1.20 [1.03, 1.39], p = .02), and for both brushing and flossing (adjusted RR = 1.33 [1.10, 1.61], p = .003). Daily flossing was more likely at 6-month follow-up (adjusted RR = 1.21 [1.04, 1.42], p = .02) among OH4L participants. The change in self-efficacy and motivation for daily flossing from baseline to 2 months was significantly greater among OH4L participants and mediated the intervention effect on flossing at 6 months. Integrating oral hygiene promotion with standard tobacco quitline services improved oral health self-care.