Objective: Between 2013 and 2014, past 30-day use of e-cigarettes increased from 4.5% to 13.4% among US high school students aged 9-19 years. We sought to examine the influence of perceived addiction and harm of e-cigarettes on e-cigarette use among adolescents. Design: Self-reported use and perception of harm of e-cigarettes were assessed using a cross-sectional design. Setting: Data were collected from the 2014 National Youth Tobacco Survey. Method: Multivariate logistic regression models were employed regressing lifetime e-cigarette use and past 30-day use on established covariate factors. Results: Perceiving e-cigarettes as less harmful than conventional cigarettes increased students' odds of lifetime use (odds ratio [OR] = 2.40, 95% confidence interval [CI] = 1.98-2.90) and past 30-day use (OR = 2.18, 95% CI = 1.63-2.92) of e-cigarettes. Perceiving e-cigarettes as less addictive than conventional cigarettes also increased students' odds of lifetime use (OR = 2.11, 95% CI = 1.82-2.45) and past 30-day use (OR = 1.93, 95% CI = 1.57-2.38) of e-cigarettes; however, perceiving e-cigarettes as more addictive than conventional cigarettes also increased students' odds of lifetime use (OR = 1.85, 95% CI = 1.37-2.49) and past 30-day use (OR = 2.68, 95% CI = 1.84-3.90) of e-cigarettes. Other influencing factors of e-cigarette use among youth included race, grade level, living with a smoker and lifetime use of regular cigarettes. Conclusion: The perception that e-cigarettes are less addictive and harmful than their conventional counterparts may be an important risk factor for the use of e-cigarettes. Factors influencing young people's perceptions need to be examined further.