Tourism has a critical role in the portfolio of economic and political measures required to approach the Aichi Targets for the expansion of protected areas. Tourism receives remarkably little attention in high-level conservation debates, but in fact it already funds >50 per cent of some national parks agency budgets and contributes >50 per cent of conservation funding for some IUCN-red listed species. In addition, managing both revenue and threats from tourism is one of the major practical preoccupations of protected area managers on the ground. The ways in which tourism can support or threaten conservation depend strongly on local social, political and legal frameworks and hence differ markedly between countries, and between different land tenures within countries. In addition, the ways in which tourism can be mobilized as a conservation tool, or avoided as a conservation threat, differ between political and socioeconomic groups within each country. This paper argues that for good or bad, tourism has become an unavoidable component of conservation efforts worldwide, and deserves far greater attention from the conservation community.