In this paper, we examine the role of trust in the international climate negotiations. We (1) identify forms of trust inferred from institutional designs, (2) analyse effects of institutional design on social and political trust and (3) describe the relationship between social and political trust in international climate change negotiations. We do this by combining document analysis, literature review and interviews. We find that the United Nations Framework Convention on Climate Change (UNFCCC), the Kyoto Protocol and the Paris Agreement imply different forms of trust and thereby produce different levels of trust. Social trust is generally medium to high, political trust rather low. Our analysis illustrates tensions and contradictions between human agency and intention, on the one hand, and political agency and process, on the other. These tensions and contradictions are such that, although delegates at the international climate conferences do at least partly trust each other, they meet in an institutional context that is marked by lack of political trust. Moving forward, we discuss whether this lack of trust is well‐founded or not given the current institutional and organisational structures of the UNFCCC and its subsequent agreements and what it is highlighting in terms of specific flaws or omissions in the UNFCCC's design.