This document charts the way forward for GGOS over the next four years. It provides a well-thought-out framework for addressing the key challenges facing GGOS. The Plan consists of 64 concrete activities defined according to SMART (Specific, Measurable, Achievable, Relevant, Time-bound) criteria. All this is the result of a collective effort based on the voluntary collaboration of many colleagues involved in the GGOS. This support is greatly appreciated.