ABSTRACT The term open source is increasingly applied to architecture, yet there is little consensus about what it means in this context. This paper explores how different literal and metaphoric interpretations of the “access to source code” principle, set by the founders of the Free and Open Source Software movements, are being applied to architecture. The authors explore several challenges that have arisen in the translation of open source rhetoric from cyberspace to architectural space and discuss paths for new conceptual and programmatic agendas promoting user empowerment and democratization in architectural design.