Theories for conceptualizing educational policies aimed at improving classroom instruction at scale are under development in the educational sciences. In using such theories, it is essential to note the specific educational context. In this article, we conceptualize the role of contextual factors when operationalizing Cobb and Jackson (2012) ["Journal of the Learning Sciences"] in the Swedish context. Drawing on data and results from a large-scale project carried out during 2012-2017 and studies of Swedish educational contexts, we conceptualize contextual factors for large-scale projects. Besides rather obvious explicit contextual factors such as ongoing policies and practices, we elaborate on how the underlying, more implicit contextual factors of (1) the positioning of teachers within the educational system, (2) the positioning of teachers within the classroom, and (3) traditions of visible and invisible pedagogy affected the establishment of policy in the Swedish context. Insight into these factors deepens earlier frameworks of context, and helps not only to operationalize the policy within the context but also to make explicit hidden features of a cultural context that are important to influence if the aim of the educational policy is to reorganize school practices.