Problem Behaviour Theory suggests that young people's problem behaviours tend to cluster. This study examined the relationship between traditional bullying, cyberbullying and engagement in problem behaviours using longitudinal data from approximately 1500 students. Levels of traditional victimisation and perpetration at the beginning of secondary school (grade 8, age 12) predicted levels of engagement in problem behaviours at the end of grade 9 (age 14). Levels of victimisation and perpetration were found to moderate each other's associations with engagement in problem behaviours. Cyberbullying did not represent an independent risk factor over and above levels of traditional victimisation and perpetration for higher levels of engagement in problem behaviours. The findings suggest that to reduce the clustering of cyberbullying behaviours with other problem behaviours, it may be necessary to focus interventions on traditional bullying, specifically direct bullying. (Contains 1 figure and 5 tables.)