Abstract.  This paper presents a theoretical framework to highlight possible channels for the international transmission of financial shocks. We first review the different definitions and measures of contagion adopted by the literature. We then use a simple multi‐country asset pricing model to classify the main elements of the current debate on contagion and provide a stylized account of how a crisis in one country can spread to the world economy. In particular, the model shows how crises can be transmitted across countries, without assuming ad hoc portfolio management rules or market imperfections. Finally, tracking our classification, we survey the results of the empirical literature on contagion.