Concerns about Islamic extremism and ongoing debates about the integration and assimilation of Muslims into Western societies continue to attract considerable attention from the media, policymakers, and scholars, but relatively little cross-national research has been done on Western attitudes toward Muslims. This article attempts to address this question by exploring 2006 Pew Global Attitudes data among non-Muslims in Britain, France, Germany, Spain, and the U.S. Using structural equation modeling, we examine the determinants of Western views toward Muslims, and find that threat perceptions are the primary factor influencing these views. Specifically, our analysis suggests that perceptions of security threats drive attitudes regarding Muslims, and that perceived cultural threats are only indirectly related to views towards Muslims.