Introduction Research suggests that adolescents who use electronic cigarettes (e-cigarettes), including adolescents not susceptible to smoking cigarettes (ie, those who have never smoked cigarettes and are not attitudinally susceptible to using cigarettes), are more likely to initiate using cigarettes or other combustible tobacco products than adolescents who do not use e-cigarettes. In this study, we examined correlates of e-cigarette use and susceptibility among adolescents not susceptible to future cigarette smoking. Methods We used data on high school students from the 2015 North Carolina Youth Tobacco Survey (n = 1,627). SAS logistic regression survey procedures were used to account for the complex survey design and sampling weights. Results Increasing perceived harm of e-cigarettes was associated with lower odds of susceptibility to using e-cigarettes (adjusted odds ratio [AOR] = 0.79; 95% confidence interval [CI], 0.65-0.96) and current use of e-cigarettes (AOR = 0.43; 95% CI, 0.25-0.72). Similar patterns were found for perceived harm of secondhand e-cigarette vapor. Exposure to e-cigarette vapor in indoor or outdoor public places was positively associated with susceptibility to using ecigarettes (AOR = 1.96; 95% CI, 1.33-2.91) and with current e-cigarette use (AOR = 5.69; 95% CI, 2.57-12.61). Conclusion To prevent initiation of e-cigarette use, particularly among adolescents not susceptible to smoking cigarettes, educational campaigns could target harm perceptions associated with e-cigarettes. In addition, regulations that limit adolescents' exposure to e-cigarettes in public places may decrease e-cigarette use by nonsusceptible adolescents