Although terrorism is an area that has been the subject of much research, systematic searches in databases reveal that a focus on actors and movements that find their motivation in Christian beliefs, is, by and large, lacking. Ever since the 9/11 terrorist attack, Islamist terrorism has been the major focus. The purpose of this thesis is to describe and compare Christian and Islamist acts of terrorism. This will be done by using the terrorist attack of the self-proclaimed Christian crusader Anders Behring Breivik in Norway 2011 and compare it to the terrorist attack in Paris November 2015 claimed by the terrorist organisation Islamic State (IS). A content analysis is used to explore the material. The analysis is conducted with an analytical framework created from previous research on religious terrorism to explore the similarities and differences of religiously motivated terrorist acts. The study reveals that there are a lot of similarities between Breivik and the Paris attackers. Both Breivik and IS strived to change society with violence justified by their religion. In a type of “God´s executioner” fashion. A final conclusion in this thesis is that Breivik and IS share Ideological core ideas in the form of exclusivity, however, the exclusivity is expressed differently. Breivik´s exclusiveness is linked to ethnicity and skin colour, while IS´s exclusivity is solely linked to faith.