The article discusses the issue which in English is referred to as “accountability” (and translated into Polish as „odpowiedzialność” or „rozliczalność”) of international organizations (IO). The most important assumption of this paper is conducting a conceptual analysis of the specific type of IO accountability, which is the accountability based on their reputation and classified by researchers as one of the accountability mechanisms involving participation in the assessment of the activities of the organizations of the entities most affected by the organizations’ actions. The theoretical background for the considerations presented in the text constitute the assumptions of social constructivism emphasizing the importance of meanings given to particular concepts by entities participating in a series of interactions and highlighting the process of the double construction in the relation subject – structure. The thesis assumes that IO’s reputation determines how they are perceived internationally and in what way their actions are classified as legitimate. Thus, reputation becomes one of the sources of their accountability. The issue addressed in the article seems to be particularly important for two reasons. First of all, the issue of accountability is related to the contemporary challenges that IO face, as they are often accused of lack of transparency in their activities, deficit of democratic procedures, etc. Secondly, international relations have become so complicated that one should constantly ask the question who is accountable for some activities, including in the framework of “Internet governance” or “global private governance”. It is no longer possible to refer to the accountability of the actors of international relations in terms defined by the term “responsibility” suggesting the responsibility for violation of the norms of international law.