Objectives: The identification of factors which influence peoples’ preparation for health safety risks posed by natural and man-made disasters is a central concern in health education. Prior studies have generally approached this issue from either a cognitive or a social influence perspective, and have failed to recognise the increased importance of terrorism-related concerns in motivating health safety preparedness behaviour. The purpose of this study was to develop a unified social cognitive framework for understanding peoples’ preparations for health safety risks, focusing on terrorism-related cognitive and social influences. Design/Method/Approach: Participants in the National Survey of Disaster Experiences and Preparedness reported preparedness actions they had taken since 2001, their appraisals of terrorism-related threat and coping, and whether they knew others who had taken preparedness actions because of terrorism. Using a logistic binomial hurdle statistical model, number of actions taken was regressed on terrorism-related vulnerability, severity, response efficacy, self-efficacy, and informational social influence. Simultaneous models both of taking any action and of the number of actions taken were tested. Findings: After controlling for demographic variables, both taking any action and the number of preparedness actions taken were positively related to terrorism-related informational social influence, response efficacy, and self-efficacy; effects of terrorism-related vulnerability and severity appraisals were much smaller. Compared to cognitive factors, terrorism-related informational social influence had a substantially larger effect on taking any action, and a moderately larger effect on the number of actions taken. Conclusion: Terrorist-related informational norms were more salient than cognitive factors in influencing peoples’ preparation for health safety risks. Participants who knew someone who had taken one or more emergency preparedness actions because of terrorism were significantly more likely to take any preparedness action, and to take more preparedness actions, themselves. These findings are consequential in developing future educational initiatives.