Research suggests that International Organizations (IOs) are getting more involved in efforts to mitigate and adapt to climate-related security risks in different parts of the world. However, there is still a limited understanding of how discourse and action on climate security develop and diffuse in and across different institutional settings in various policy fields and geographical contexts. This article aims to contribute to advancing the research agenda by outlining an analytical framework that helps structure comparison across IOs along three key dimensions: (a) discursive framing; (b) institutional design; and (c) policy actions. To illustrate how the framework can be used in empirical analyses the article discusses findings from previous research. This is not only relevant to highlight the framework’s analytical usefulness as it also shows the relevance of these research findings for practitioners and decision-makers engaged in efforts to enhance the role of IOs in global governance of climate security—and across the humanitarian-development-peacebuilding nexus.