Objective: E-cigarette use is prevalent amongst young Australians, and recent studies confirm e-cigarette use has detrimental short and long-term effects on health. This study evaluated the extent to which e-cigarette outcome expectancies and refusal self-efficacy predict lifetime e-cigarette use in young Australians. : Participants were 263 young Australians ( = 20.4; 82.1% female). Participants completed an online survey assessing e-cigarette use, e-cigarette outcome expectancies, and e-cigarette refusal self-efficacy. Lifetime e-cigarette use was regressed on e-cigarette use outcome expectancies and e-cigarette refusal self-efficacy, with age, gender, and education as controls. : E-cigarette use outcome expectancies and e-cigarette refusal self-efficacy significantly predicted lifetime e-cigarette use, while controlling for demographic variables. Stronger e-cigarette dependency expectancies were associated with a lower likelihood of lifetime e-cigarette use. Stronger external refusal self-efficacy was associated with a lower likelihood of lifetime e-cigarette use. : E-cigarette use intervention and prevention programs may benefit from strengthening awareness of dependency on e-cigarettes, particularly in the Australian context where the presence of nicotine in e-cigarette liquids is likely to be far more widespread than initially believed.