This is the final version of the article. Available from the publisher via the DOI in this record. ; Animals often use social information about conspecifics in making decisions about cooperation and conflict. While the importance of kin selection in the evolution of intraspecific cooperation and conflict is widely acknowledged, few studies have examined how relatedness influences the evolution of social information use. Here we specifically examine how relatedness affects the evolution of a stylised form of social information use known as eavesdropping. Eavesdropping involves individuals escalating conflicts with rivals observed to have lost their last encounter and avoiding fights with those seen to have won. We use a game theoretical model to examine how relatedness affects the evolution of eavesdropping, both when strategies are discrete and when they are continuous or mixed. We show that relatedness influences the evolution of eavesdropping, such that information use peaks at intermediate relatedness. Our study highlights the importance of considering kin selection when exploring the evolution of complex forms of information use. ; Dr. Baker was supported by a fellowship from the Department of Organismic and Evolutionary Biology at Harvard University, and by National Science Foundation (NSF) SES-0750480 and the European Science Foundation/European Collaborative Research (ESF/EUROCORES) program’s support for the The Evolution of Cooperation and Trading (TECT) project. Dr. Rankin thanks the Swiss National Science Foundation (Grants 31003A-125457 and PZ00P3-121800) and the University of Zu¨rich Forschungskredit, and Dr. Dall thanks the Natural Environment Research Council UK (NE/D014352/1) for funding. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.