OpenSchoolMaps is a project to promote open maps in the classroom, be it in digital form, in the browser, on mobile devices or printed. The project mainly uses free data from OpenStreetMap. It is aimed at teachers at upper secondary level (secondary schools and grammar schools) and other interested parties, like self-learners. The maps and map data as well as the teaching and learning materials are provided as Open Educational Resource (OER), so that everyone can contribute to the teaching and learning materials and use them freely - even outside the classroom! - and can and may pass them on.