Book excerpt: The six countries of the Greater Mekong Subregion (GMS) are striving to ensure an adequate, reliable, sustainable, and affordable energy supply for all their citizens. Toward this, the GMS countries have identified power trading as a priority for regional cooperation. However, such trading currently represents less than 2% of electricity consumed in the GMS. This publication examines the regulatory and commercial barriers that are preventing a greater uptake of power trading in the region and identifies the key measures needed to overcome them.