The influence of peer victimisations on sexual behaviour among senior secondary students has not been attracting proper attention from researchers probably because of the fact that it is not perceived as a serious social or educational problem. However, in recent time there has been a growing concern on the increasing level of student unrest, sexual victimisation, violence and cultism in Nigeria secondary schools, thus portend a great danger for the nation. This study therefore examined the influence of peer victimisations on the sexual behaviour of the students with a view of finding out the relationship and suggested ways of coping with the problem.The sample consisted of three hundred participants drawn with random sampling technique from ten selected senior secondary schools in both Oyo and Bayelsa states of Nigeria. Two valid and reliable instruments constructed by the researchers were used for data collection: Peer Victimisation Scale (PVS) (r =0.70) and Sexual Behaviour Scale (SBS) (r =0.72). The administration lasted four weeks, using simple percentages and correlation analysis. The results show that peer victimisations contributed to sexual behaviour of the students. On the strength of the findings, the need to foster good peer relations to enhance positive sexual behaviour among students was stressed and advocated.