Objective. Growing research focusing on citizens' psychological reactions to terrorism finds that attacks perpetrated by individuals belonging to Muslim minorities increase negative attitudes toward immigrants as a whole. We argue that this empirical regularity might be explained by stereotyping, which produces immediate emotional reactions among people holding exogenously positive/neutral attitudes toward immigrants. Methods. We employ a quasi-experimental before-after design based on the Manchester bombing of May 22, 2017. Results. Evidence is consistent with the stereotyping effect hypothesis as shown by the temporality of the effect on citizen's attitudes: the effect is indeed strong and significant in the first three days after the attacks for the more cosmopolitan citizens. After four to seven days, however, the effect disappears for every group. Conclusion. The study suggests that the impact of terrorism on public opinion is consistent with a stereotyping effect and therefore, although immediately strong, it lasts very little in time.