The evaluation of opportunities to introduce new goods or services to one or more markets is an essential part of entrepreneurship, and the last decade ushered in a steady stream of studies on the topic. However, to date, this knowledge has not been systematically reviewed. The current article addresses this gap by synthesizing studies that speak to the evaluation of entrepreneurial opportunities. The review of 53 articles involves the development of a thematic framework used to organize the literature in terms of conceptual and empirical themes as well as patterns in publication trends. The insights derived culminate in an integrative framework that conceptually describes what goes on in the ‘mind in the middle’ as opportunity evaluation unfolds. The model illuminates a path for future research that guides improved understanding of the cognitive dynamics that lead some individuals to believe that a set of circumstances represents an attractive opportunity while others have little confidence that the same circumstances represent an opportunity at all.