This special issue interrogates the contexts in which reforms are developed as well as the contexts to which they spread in order to understand the factors that influence the potential for reforms to be scaled up. Four articles from around the world address this understudied role of context. In our analysis of these articles, we take an ecological view, one that encompasses each of these challenges to explore the interplay between educators’ experiences, beliefs, and their contexts regarding reform. We begin to elaborate a theory of scale derived from medical research that develops a seed and soil application to educational research. In this theory, we describe how a discrete focus on the content of reform is no longer adequate; rather, an approach that also addresses the context and whether and to what extent it is supportive of change must also be considered. The features of supportive contexts are enumerated, including size, locus of control, norms, sociocultural context, and socioeconomic context. Three reforms are analyzed using these features as a framework. We conclude that the extent to which these conditions are prevalent may point to the capacity of a system to support a new reform.