Comparative work on income taxes in developing countries has commonly looked at average tax rates. These rates are often constructed by dividing revenue collections by some measure of private or personal income. Recent controversies have, however, focused on the incentive effects of marginal tax rates. This article develops and applies a simple methodology to compare marginal official tax rates across a sample of fifty developing countries. As would be expected given differences in fiscal capacity, the poorest and the lower-middle-income countries impose relatively low marginal rates, and the rates for the upper-middle-income and developed countries are higher. Conversely, several low-and lower-middle-income countries' tax thresholds start at income levels which are low relative to their mean income when compared with those of developed countries. The results warn against trying to derive information on the disincentive effect of a country's tax schedule from the highest marginal rate; our data show that this is not an accurate indicator of overall disincentive effects.