Terrorist attacks committed in 2003 by Turkish Islamist extremists threatened the social identity of Turkish Muslims by associating them with terrorism. Using a 2 × 3 experimental design, we categorized Turkish respondents and terrorists as members of a shared superordinate group (“Muslims”) or as members of separate subgroups. When sharing superordinate group membership with terrorists, less identified Turkish respondents experienced ambivalent identification, i.e., they sought to maintain attachment to their group while simultaneously seeking distance from it. Ambivalent identification was reduced when respondents emphasized their typicality as members of a Muslim subgroup that did not include terrorists. The discussion focuses on ambivalent identification as a response to identity threat, and the implications for Islamist terrorism for the social identity of Muslims.