Ecotourism is often promoted for its potential to act as a conservation mechanism by: mobilising political, financial and social support for conservation; increasing environmental awareness; protecting sensitive ecosystems and threatened species; and providing an alternate income to land-intensive or consumptive practices. Although instances to date indicate that this can indeed prove highly successful in some circumstances, the conservation impact of the ecotourism sector on a larger scale is unclear. This study identified 70 papers published prior to January 2016 in English language academic journals that examine the conservation actions and outcomes of ecotourism enterprises. There were three key findings within this study. Firstly, conservation actions have been examined more frequently than conservation outcomes. Secondly, there has been a strong focus on indirect approaches to conservation such as visitor education and community-based actions, and a shortage of studies measuring direct impacts on wildlife populations or other components of the natural bio-physical environment. Thirdly, the majority of sites studied are located in developing countries, but the majority of authors are located in developed countries. By identifying these gaps and patterns that currently exist in the academic literature, this review helps to direct and support future research agendas.