This paper is concerned with the twinning of sustainability with priorities of economic neoliberalization in education, and in particular via the mobility or diffusion of education policy. We discuss the literature on policy mobility as well as overview concerns regarding neoliberalism and education. The paper brings these analyses to bear in considering the uptake of sustainability in education policy. We ask to what extent sustainability as a vehicular idea may be twinning with processes of neoliberalization in education policy in ways that may undermine aspirations of, and action on, environmental sustainability. Toward the end of the paper, we draw on data from an empirical study to help elucidate how the analytic frames of policy mobility can inform our analyses of the potential concerns and possibilities of sustainability as a vehicular idea. In particular, we investigate how sustainability and related language have been adopted in the policies of Canadian post-secondary education institutions over time. The paper closes by suggesting the potential implications of the proceeding analyses for policymakers, practitioners, and researchers concerned with sustainability in education policy.