Background: Tobacco smoking causes 19,000 deaths per year in the Netherlands. Since 2007, a reduced-risk product is on the Dutch market: the electronic cigarette (e-cigarette). An e-cigarette delivers nicotine without many of the cancer causing and other toxic substances that are present in combustible tobacco smoke. Although some mainly see the harm reduction potential of e-cigarettes, others have concerns that e-cigarettes may appeal to youth and form a gateway to tobacco smoking. In the Netherlands, 39% of the 14-year olds report to have used e-cigarettes. Previous research: Researchers from the USA have examined smoking initiation among adolescents who experimented with e-cigarettes. They found that those who experimented with e-cigarettes were more likely to start smoking combustible tobacco products over the next year. It is important to ascertain whether this finding can be replicated in other countries. Approach: We will replicate the study from the USA by surveying a school-based cohort of adolescents in the Netherlands at baseline, after 6 months, and after 12 months. Main outcome measure is use of tobacco products within the prior 6 months at follow-up. Analyses are adjusted for sociodemographic, environmental, and intrapersonal risk factors for tobacco smoking. Implications: The findings from this study will have important implications for national and school policy and education. If the findings from the USA are replicated in the Netherlands, this is an indication that use of e-cigarettes among adolescents may be a gateway to tobacco smoking. Then, it will be important to prevent e-cigarette experimentation among adolescents. There are already some national policies in place in the Netherlands, but these could be expanded (e.g. licensing e-cigarettes as medicines instead of having them available as consumer products). Also, educational efforts to decrease e-cigarette experimentation may then need to be implemented, which is already being done in the USA.