Studies across multiple disciplines demonstrate the importance of peers in shaping energy-related behaviours. Research on this process is wide ranging, from documenting spatial peer effects in the adoption of rooftop solar—when an individual’s behaviour is influenced by the behaviours of neighbours—to showing how neighbour comparisons can be used to reduce household electricity consumption. However, gaps exist in our understanding of how and why these peer effects occur. In this Review, we examine recent findings on social influence in energy behaviour and discuss pathways through which social influence can result in peer effects. We propose a conceptual framework for predicting which social influence processes will most often result in peer effects, depending on the targeted energy behaviour. We also review the limitations of social influence as well as evidence for when it is expected to be the strongest.