The effectiveness of e-cigarettes in smoking cessation is under debate. Informing smokers who are motivated to quit smoking about e-cigarettes may help them to make an informed decision about their use for smoking cessation, which, however, may also lead to unintended effects such as less quitting. This experimental study assessed the influence of providing tailored information about e-cigarettes in a web-based tailored smoking cessation intervention on participants' decision-making and smoking behavior. Adult smokers (N = 331) were randomized into a personalized eHealth intervention on (i) smoking cessation (control condition) or (ii) smoking cessation and information about e-cigarettes (intervention condition). Directly postintervention, participants in the intervention condition had more knowledge about e-cigarettes than participants in the control condition. Attitudes toward e-cigarettes were more positive among intervention participants than control participants, but the differences in attitude were less pronounced than the differences in knowledge and not consistent across items. At a 6-month follow-up, no between-condition differences were observed in the use of e-cigarettes as a smoking cessation method, the number of tobacco cigarettes smoked in the past 7 days, or other smoking outcomes.