This paper examines tax revenue shortfalls in South Asian countries. On average during 2019-23, South Asian revenues totaled 18 percent of GDP-well below the average 24 percent among emerging market and developing economies (EMDEs). Econometric estimates from stochastic frontier analysis, which control for tax rates and the size of potential tax bases, suggest that tax revenues in the region are 1 to 7 percentage points of GDP below potential, with shortfalls in five of the region's eight countries larger than in the average EMDE. Even after controlling for country characteristics, such as widespread informal economic activity outside the tax net and large agriculture sectors, sizable tax gaps remain, suggesting the need for improved tax policy and administration. The paper discusses and provides evidence from international experience with reforms to raise government revenues.