This article provides theoretical and empirical solutions to two connected puzzles in the study of foreign aid and human rights: Do foreign aid donors use aid sanctions to punish repressive states, and if so, why? I show that donors impose aid sanctions selectively. Aid sanctions typically occur when repressive states do not have close political ties to aid donors, when violations have negative consequences for donors and when violations are widely publicized. Using a data set of bilateral foreign aid to 118 developing countries between 1981 and 2004, I find that variation in these factors largely accounts for the differing aid sanctions that result from objectively similar rights violations by the governments of developing countries.