The public reactions after terrorist attacks in Europe in recent years, such as the Utøya massacre, the Charlie Hebdo attack, and the Manchester Arena bombing, only to name a few, have been vast and diverse, and not the least on social media platforms. Moa Eriksson Krutrök’s thesis explores how social media is used during and after terrorist attacks such as these. The thesis aims to explore how digital platforms may alter or transform the ways in which such attacks are collectively understood and interpreted. Methodologically, the thesis uses a combination of methods, such as network analysis of hashtag co-occurrences and thematic content analysis, in order to develop a more detailed understanding of the discursive articulations taking place on social media following terrorist attacks. In the four specific studies, different cases of terrorist attacks are analysed, where social media has been prominent in shaping the ways in which they have been discursively articulated.