The World Health Organization reported that smoking is a primary health risk factor. The prevalence of e-cigarette use in adolescents has increased recently. However, the association of e-cigarette use with smoking intentions and behaviors is unconfirmed. Through PubMed, PsycINFO, CINAHL, and Airiti Library, this study systematically reviewed studies published in English or Chinese language that have examined the association of adolescent's e-cigarette use with smoking intentions and behaviors from January 2014 to February 2018. We identified 18 empirical studies satisfying the respective criteria. Most of the studies had cross-sectional designs and were from the United States; only a few longitudinal studies had follow-up periods of less than 1 year. Based on the Theory of Reasoned Action, this systematic review provided some evidence of positive associations between e-cigarette use and smoking intentions, smoking behavior, and smoking frequency among adolescents. Future research must investigate the association of e-cigarette use with smoking-related behaviors by using longitudinal designs with long-term follow-ups to determine the respective causality for informing subsequent policymaking and research.