In the era of 9/11, terrorist attacks occur with sufficient frequency and lethality to constitute a realistic threat to the well-being of the American public. Sensing this concern, politicians emphasize the threat of violent attacks to advance a platform of making public safety a priority. In this context, the authors assess the extent, sources, and emotional impact of the public’s concern about terrorism. On the basis of a national survey of 1,000 Americans, the authors examine levels of fear of a terrorist attack and worry about terrorism relative to other potential harms. They also determine whether concern about terrorism translates into support for homeland security measures that target Muslims. Of the predictors in the authors’ models, gender, religiosity, and psychological distress were most consistently associated with fear of terrorism and worry about being a victim of a terrorist attack. Structural equation modeling demonstrated that terrorism-related fear and worry predict support for anti-Muslim policies.