Open schooling uses distance education methods and technology to scale education access. It can complement traditional schools. The Open Educational Resources for Open Schools (OER4OS) project aimed to develop open educational resources (OER) in 20 subjects at secondary level. OER were created in multimedia format for 5 subjects and in Moodle format for 12 subjects. Building teacher capacity for using technology and developing OER is key. Challenges included getting subject teams to communicate using collaboration tools, timely authoring of print materials, and communicating with coordinators. The evaluation process discouraged some participants. Critical success elements included leadership, monitoring and evaluation, and community engagement.