Manufacturers as well as retailers can suffer important losses as a result of stock-outs. The magnitude of these losses depends on specific consumer reactions, which have been found to vary with product, consumer, and situation factors. This paper presents a conceptual framework that integrates the major determinants of consumer reactions to stock-outs. The theoretical relationships provide explanations for the marked differences in stock-out effects observed in previous studies. Moreover, the framework can be empirically implemented, allowing retailers and manufacturers to determine how much each factor contributes to stock-out losses. We collect survey data to provide evidence on the relevance of the framework and the direction and importance of the effect of different consumer behaviors.