The analysis of risk in tourism is fragmented and uneven and focuses relatively narrowly on risk as a set of negative outcomes to be avoided by individuals, firms, or destinations. This article contends that, because of general, and sector-specific, limitations to knowledge, systematic and unsystematic risks are central to all forms of tourism activities. There is a need for a stronger theoretical understanding of the different concepts of tourism risks and tourism uncertainties that engages with how these are manifested at different scales, and can be analyzed from competing perspectives. The contribution and potential of both rationalist and constructivist approaches are assessed, focusing on individuals, firms, intermediaries, and destinations. The article concludes by identifying priorities for future research relating to both theoretical positioning and scale-specific issues ranging from individual decision making to the securitization of national tourism policies.