Abstract: The South Asia region is lagging behind many regions in the world in regional electricity cooperation and trading, despite the huge anticipated benefits. This study uses an electricity planning model that produces optimal expansion of electricity generation capacities and transmission interconnections in the long-term to quantify the benefits of unrestricted cross-border electricity trade in the South Asia during 2015–40. The study finds that the unrestricted electricity trade provision would save US$226 billion (US$9 billion per year) of electricity supply costs over the period.