Victims of online abuse suffer measurable negative effects equivalent to survivors of traumas such as bombings and sexual assaults but it has been suggested that the general population view such online behaviour as acceptable, with victims consequently receiving little support. This is an issue of increasing import as the number and accessibility of online communication apps, and their incorporation into our everyday lives, increases the opportunity for Deviant Online Behaviours (DOBs) to be perpetrated. In order to better understand individuals’ attitudes to specific DOBs 118 psychology undergraduate students rated 11 examples of DOBs on a scale of severity. Individual difference measures of online cognitions and interpersonal sensitivity were also collected. A factor analysis revealed 3 emerging online behaviour types: use of false information (theft of identity, tricking others), unsolicited behaviour (unsolicited e-mailing/messaging), and persistent communication (frequent contact and use of multiple identities). ‘Persistent communication’ was viewed as more unacceptable than ‘unsolicited behaviour’ and ‘false information’, though all contained behaviours which have been demonstrated to cause severe harm to victims. These findings attempt to demonstrate how individuals categorise deviant online behaviours in terms of severity and individual differences that may be associated with these perceptions.