We introduce a “reason-based” framework for explaining and predicting individual choices. The key idea is that a decision-maker focuses on some but not all properties of the options and chooses an option whose “motivationally salient” properties he/she most prefers. Reason-based explanations can capture two kinds of context-dependent choice: (i) the motivationally salient properties may vary across choice contexts (as in framing effects); and (ii) they may include context-related properties (such as whether an option conforms to a context-specific social norm). By contrast, classical choice theory admits neither of these two kinds of context-dependence. Our framework allows us to explain boundedly rational and sophisticated choice behaviours, such as those discussed in psychology and behavioural economics. Since motivationally salient properties can be recombined in new ways, the framework offers resources for predicting choices in unobserved contexts, a somewhat neglected issue in standard choice theory. The paper also compares our reason-based approach with the more traditional revealed-preference approach.