There are about 2,600 double tax treaties in the world, some 500 among industrialized economies, approximately 800 among developing economies and about 1,300 between industrialized and developing economies. Whereas the prior two categories are symmetric, the latter is asymmetric, as capital flows predominantly from industrialized to developing economies, and capital income the other way round. This article asks which developing countries have double tax treaties, whether with other developing countries or with industrialized countries. The results of the econometric analysis suggest that geography, size (GDP) and openness matter. Finally, political variables, such as colonial status, political similarity, and most strikingly development aid are correlated with the existence of a double tax treaty.