In times of a high-impact safety incident citizens may have a variety of sources available to help them cope with the situation. This research focuses on the interplay of efficacy information in risk communication messages and peer feedback, such as responses on social network sites (SNSs) in the context of a high-impact risk on the intention to engage in self-protective behavior. The study pitted high and low efficacy information messages against supporting and opposing peer feedback (N = 242). Results show a significant interaction effect between efficacy information in a news article and peer feedback from SNS messages on both the intention to engage in self-protective behavior and levels of involvement. Participants who received the article with more efficacy information and also received supportive peer feedback via SNS messages were more likely to express higher levels of involvement and greater intentions to engage in protective behavior. When confronted with a low efficacious news article, the effect of peer feedback on these two variables was significantly stronger. Finally, implications for theory and government risk communication are discussed.