While a mega-event is scheduled at least once every year somewhere in the world, these events are rare occurrences for the host cities and countries. The benefits of such events seem lucrative; the very fact that many countries bid to host these events suggests that the benefits – be they tangible or intangible – more often than not outweigh the costs. Using a standard gravity model of bilateral tourism flows between 200 countries from 1995 to 2006, this paper measures a very direct benefit of such mega-events: the increase in tourist arrivals to the host country. Although ex ante expectations are that tourism numbers would increase significantly during such an event, a growing literature points to the careful appraisal of possible tourist displacement, i.e. ‘regular’ tourists that change their behaviour when a mega-event is held, either shifting their trip to a different time or different location. This may result in reduced tourism gain, or even loss. In general, results suggest that mega-events promote tourism but the gain is dependent on the type of mega-event, the participating countries, the host country’s level of development, and whether the event is held during the peak- or off-season.