This study examines the impact of terrorist attacks on public attitudes toward immigration in European countries and Turkey, focusing on differences in Islamic terrorism and direct / indirect effects. Using Eurobarometer survey data from 1990 to 2018, combined with the Global Terrorism Database (GTD), the research analyzes how the occurrence, magnitude, and type of terrorist attacks influence public perceptions of immigrants over time. The study applies group threat theory to understand how fear and prejudice are shaped by factors such as religiosity, political affiliation, and demographic characteristics. Results indicate that Islamic terrorist attacks, due to their association with radical Islamist ideologies, elicit stronger anti-immigrant sentiments compared to non-Islamic attacks. Additionally, larger-scale attacks with higher casualties intensify negative attitudes, particularly among individuals with low religious commitment and conservative political affiliations.