The ability to violate and the duty to protect human rights have traditionally been ascribed to states. Yet, since international organizations increasingly take decisions that directly affect individuals, it has been alleged that they, too, have human rights obligations. Against this background, we can witness a trend among international organizations establishing provisions to prevent human rights violations and to enable individuals to hold them accountable for such violations. This can be seen as a specific manifestation of a more general trend that has been described as the spread of good governance standards to, or the constitutionalization of, international organizations. The purpose of this article is to reveal the mechanisms that can account for the introduction of human rights protection provisions in international organizations. The empirical basis of the article forms a case study on the evolution of such provisions in United Nations sanctions policy. I first develop a conceptual framework that draws on diffusion mechanisms that have been used to explain the spread of norms and institutional design among states and to trace reform processes in international organizations. The empirical analysis suggests that shaming, defiance, litigation and instances of learning can account for the advancement of human rights protection provisions in United Nations sanctions policy: the Security Council was exposed to and responded to various forms of pressure from a variety of different actors. At the same time, it was approached with arguments concerning why it should institute reforms and advice in terms of how such reforms should look and engaged in a learning process.