Depression and anxiety have been associated with cigarette use among young people. Higher impulsivity has also been associated with increased smoking behavior. However, relatively less is known about the associations between depression, anxiety, impulsivity and e-cigarette use and how these associations compare with the associations between depression, anxiety, impulsivity and cigarette smoking. In addition, little is known about how impulsivity influences the relationships between depression, anxiety, cigarette, and e-cigarette use. This study tested the hypothesis that higher depression and anxiety symptoms are associated with higher e-cigarette use and cigarette smoking in a similar way, and that these associations would be stronger among those with higher impulsivity. A sample of 2,622 young adults (18-25 year olds; 54% women) enrolled in 4-year and 2-year colleges in Hawai'i participated in a cross-sectional survey. Approximately 68% of the sample reported no use of either e-cigarettes or cigarettes, 13% reported only e-cigarette use, 9% reported only cigarette smoking, and 11% reported use of both. The study found that higher depressive and anxiety symptoms and higher impulsivity were significantly associated with current cigarette and e-cigarette use. For example, one unit increases in depression, anxiety, and impulsivity were associated with 34%, 17%, and 38% increased odds of e-cigarette use versus non-use, respectively. Impulsivity was found to significantly moderate the association between higher anxiety and higher cigarette smoking, such that the association was stronger among those with higher impulsivity. Impulsivity was not found to moderate any other association. Results suggest that tobacco product use prevention education should target children and young adults with higher internalizing symptoms, with particular attention to those who show higher impulsivity.