The release of school data – i.e. all information about school inputs, processes, and/or outputs that are shared with the general public – is being implemented in a growing number of countries. These data equip citizens with a powerful tool to exert social control over the use of public resources, and thereby help them to stand up for their rights. To help decision-makers and educational planners and managers take informed decisions regarding the development of open school data (OSD) policies, this document formulates eight key principles: from considering OSD as a public good building on existing information systems, to giving priority to data that can drive positive change, and addressing ethical risks up front.