AbstractWe analyze the evolution of the plant size distribution, static allocative efficiency and business dynamism of the Korean manufacturing sector during its growth miracle (1967–2000) and the subsequent slowdown since 2000. The average plant size has an inverse‐U pattern over time, with a peak in the late 1970s. The measure of static misallocation decreases modestly until 1983 but increases substantially afterwards. These results are at odds with what one may extrapolate from the existing cross‐country evidence on the positive relationship between plant size and economic development or the negative one between static misallocation and development. We also find that the growth rate of manufacturing productivity is not systematically correlated with either the level or the rate of change of the average plant size or static misallocation. On the other hand, business dynamism, measured by either churning or responsiveness to shocks, diminished significantly since 2000, coinciding with the decline in the growth rate of manufacturing productivity. Our findings call for more systematic research on how economic performance correlates with establishment/firm size distribution and with static and dynamic allocative efficiency.