Geothermal energy is an essential component for the successful decarbonization of the global energy supply. Its success will depend both on technological progress and on public reaction to this technology. The goal of this study is to analyze how deep geothermal energy has been discussed in the mass media in Switzerland, with an emphasis on the actors, as well as on the arguments and frames they use. We analyze media articles published from 1997 to 2013 in two major Swiss newspapers. In addition to scrutinizing arguments in favor of or against deep geothermal energy, we cluster them around four major frames–energy transition, risks, technology, and costs–with the first and second being the most prevalent. We compare which actors promote which frames and show that industry predominantly focuses on the technology's potential for energy transition, while science presents information about risks. We discuss how these frames might impede the future development of deep geothermal energy and conclude by stressing the importance of transparency and public engagement in the siting process of future geothermal projects.