The present paper aims to review open and distance learning in the context of present challenges and opportunities, describe relevant concepts and contributions, outline some significant current global and regional trends, suggest policy and strategy considerations and identify UNESCO's initiatives in this area, including its role in capacity building and international co-operation. The globalization of distance education provides many opportunities for developing countries for the realization of their education system-wide goals. Two main factors have led to an explosion of interest in distance learning: the growing need for continual skills upgrading and retraining; and the technological advances that have made it possible to teach more and more subjects at a distance.