Until now various quantitative studies have shown that adults and students in the Netherlands have low flood risk perceptions. In this study we interviewed fifty 15-year-old students in two different flood prone areas. In order to find out how they think and reason about the risk of flooding, the mental model approach was used. Flood risk turned out to be not very salient and the mental models had a piecemeal character with fundamental misconceptions. Furthermore, the mental models consisted largely of descriptive concepts instead of concepts about underlying processes with respect to explaining and predicting flooding. Concepts with respect to hazard adjustments and disaster response were lacking most. Conclusions about how to use the results of this study in geography education were discussed.