Advancing solar geoengineering research is associated with multiple hidden injustices that are revealed by addressing three questions: Who is conducting and funding solar geoengineering research? How do those advocating for solar geoengineering research think about social justice and social change? How is this technology likely to be deployed? Navigating these questions reveals that solar geoengineering research is being advocated for by a small group of primarily white men at elite institutions in the Global North, funded largely by billionaires or their philanthropic arms, who are increasingly adopting militarized approaches and logics. Solar geoengineering research advances an extreme, expert–elite technocratic intervention into the global climate system that would serve to further concentrate contemporary forms of political and economic power. For these reasons, we argue that it is unethical and unjust to advance solar geoengineering research.