This article analyzes which factors promote or hinder ratification by nation-states of the Second Optional Protocol to the International Covenant on Civil and Political Rights, the only universal treaty aimed at the abolition of the death penalty. The study finds that a democratic regime, a left-wing oriented government, regional peer influence and a high level of economic development speed up ratification. A legal system built on common law and, if less robustly, ethnic fractionalization lower the likelihood of ratification. These results are compared to the determinants of domestic death penalty abolition. Besides similarities, one striking difference is that Eastern European country membership in the Council of Europe has been important for domestic abolition, but has had no influence on ratification of the Second Optional Protocol. Western European countries exerted pressure on Eastern European countries to abolish the death penalty, but did not extend their pressure towards a ratification of the Second Protocol. Also, whereas economic development does not matter for domestic abolition, an internationally binding commitment to abolition becomes more likely the richer the country.