Ecotourism originated in the 1980s, at the dawn of sustainable development, as a way to channel tourism revenues into conservation and development. Despite the win-win idea, scholars and practitioners debate the meaning and merits of ecotourism. We conducted a review of 30 years of ecotourism research, looking for empirical evidence of successes and failures. We found the following trends: Ecotourism is often conflated with outdoor recreation and other forms of conventional tourism; impact studies tend to focus on either ecological or social impacts, but rarely both; and research tends to lack time series data, precluding authors from discerning effects over time, either on conservation, levels of biodiversity, ecosystem integrity, local governance, or other indicators. Given increasing pressures on wild lands and wildlife, we see a need to add rigor to analyses of ecotourism. We provide suggestions for future research and offer a framework for study design and issues of measurement and scaling.