The sustainability agenda is a concern of several UN agencies that appreciate how well-being, social justice, human development and the health of our planet are inextricably linked. This remit underpinned the launch of the UN Decade in Education for Sustainable Development (DESD) in 2005. As the DESD reaches its mid-point, mechanisms for assessing progress towards sustainability through education and learning have been formalised. This paper presents the Global Monitoring and Evaluation Framework (GMEF) which has been adopted by UNESCO to review changes in context structures (cycle I); processes and learning (cycle II) and outcomes and impacts (cycle III) during the DESD. The GMEF draws from the global milestones and major education for sustainable development (ESD) thrusts identified in UNESCO's International Implementation Scheme. It combines self-reporting, and participatory monitoring and expert evaluation to increase opportunities for engagement as well as to assure representation and validity of data. The paper concludes that the task of assessing global progress in ESD in an ambitious one. It identifies key challenges which will need to be overcome. (Contains 1 note.)