This paper examines the promises made in education policy regarding people's future education, employment and social mobility. Specifically, the paper analyses how the term "potential" functions in education policy texts and discourses to make tacit promises at an affective level. Contemporary education policies often invoke the need to realise personal and national economic potential, and speak of the risk of "wasted potential," when justifying reform agendas directed at both increasing human capital investment and reducing educational inequity. Drawing on the work of Gilles Deleuze, the paper develops a philosophical concept of potential that provides a theoretical framework for the analysis. The aim of the paper is to analyse how the term "potential" functions in policy to: (a) couple economic and equity purposes for education; and (b) imply a relationship between talent, opportunity and aspiration, and particular a distribution of responsibility between governments and citizens for "realising potential." While primarily theoretical, the paper is informed by analyses of interview data and documents in two research projects: (1) a small pilot study of higher education equity policy in England and Australia since the mid-1990s and (2) a study of the expansion of human capital theory and large-scale educational assessments to include non-cognitive skills. The paper diagnoses the potential of "potential" as a key word in policy and raises questions about the risks of becoming invested in the promises of education to "realise potential."