Abstract   After 9/11, public attitudes on numerous social issues changed. While many studies have examined post-9/11 attitude trends on specific topics, such as civil liberties or war, few have investigated the scope and variety of these effects. Did the events of 9/11 have a brief effect on a limited number of attitudes, or did they produce numerous, long-term changes in the way Americans think, feel and act? Drawing on a broad range of pre–post-9/11 studies, this review essay begins to answer this question by developing a framework for categorizing these effects and distinguishing short-term changes from long-term ones. The framework is intended to help facilitate an interdisciplinary social scientific research agenda on the effects of 9/11 and other terrorist acts. The essay concludes by explaining the social importance of the public's response to terrorism and the need for further research on this topic.