We analyze the effect of the Islamist terror attack in Strasbourg, France, on December 11, 2018, on social trust and attitudes towards immigration by comparing responses in the European Social Survey, before and after the attack. We find that, while the overall effects are mild, there is a strong divergence in attitudinal changes between supporters of the left, the center, and the right in a country that is deeply politically divided. • Analyzes the effect of the 2018 Islamist terror attack in Strasbourg on social cohesion. • Terror erodes trust in the center of the political spectrum, but not on the left or the right. • Attitudes on immigration improve for supporters of the left, not for those of the center or the right. • Terror deepens existing political cleavages on immigration attitudes.