Although much literature has focused on prejudice-based traditional bullying, there are not a lot of studies about prejudice-based cyberbullying. This kind of cyberbullying reflects any form of cyberbullying based on a group affiliation or identity characteristics of the victim, often including historically marginalised and other “protected characteristics” (race, religion, disability, etc.). In this chapter, we focus on seven characteristics that were highlighted in previous research – family origin, skin colour, religion/belief, nationality/ethnicity, disability, poverty, and sexual orientation. We begin by reviewing research into prejudice-based cyberbullying and emphasise the main gaps in the existing knowledge. We then present our empirical findings based on an online study that contributes to filling these gaps: (a) the prevalence of prejudice-based cyberbullying and cybervictimisation at the cross-national level, across 17 countries and including culturally diverse samples (N = 5,215 high school students); and (b) the relationships of belonging to some of the marginalised groups (based on sex, nationality/ethnicity, religion, asylum status, and disability) with both prejudice-based cyberbullying and cybervictimisation. Finally, we refer to some suggestions for future research and conclude with the implications for prevention programmes based on the obtained results.