This report analyzes how closer regional connectivity and economic integration between South Asia and Southeast Asia can benefit both regions, with a focus on the role played by infrastructure and public policies in facilitating this process. It examines major developments in South Asian-Southeast Asian trade and investment, economic cooperation, the role of economic corridors, and regional cooperation initiatives. In particular, it identifies significant opportunities for strengthening these integration efforts as a result of the recent opening up of Myanmar in political, economic, and financial terms. This is particularly the case for land-based transportation--highways and railroads--and energy trading. The report's focus is on connectivity in a broad sense, covering both hardware and software, including investment in infrastructure, energy trading, trade facilitation, investment financing, and support for national and regional policies.