Korea's rapid growth has slowed in recent years, suggesting lower potential growth. This paper uses an array of techniques, including statistical filters, a multivariate model and the production function, to estimate Korea's potential growth. The main finding is that trend growth has fallen from around 4¾ percent during 2000-07 to around 31/4 -31/2 percent by 2011-12. Absent reforms, it is projected to fall further to around 2 percent by 2025, primarily due to declining working-age population. However, Korea's potential growth can be maintained at a higher level by putting in place a comprehensive structural reform agenda, including increased female and youth labor force participation, liberalization of product and labor market regulation. Staff simulations suggest that such reforms could lift potential growth by around 11/4 percentage point over the next decade, maintaining potential growth at around 31/4 percent, counteracting the effect of population aging, and enabling Korea to continue to converge to income levels of the United States.