Background Cyberbullying, described as, “a form of aggression involving the use of information and communication technology to post or send harassing or embarrassing messages to another person”, is an emerging global problem. This study presents findings on the prevalence and factors associated with cyberbully victimisation among secondary school adolescents in Oyo state, Nigeria.

Methods A cross-sectional study that utilised a multi-stage sampling technique to select 653 students from schools within the state was conducted. Information on students’ socio-demographic characteristics and history of cyberbullying in the three-month preceding the study was obtained from the students.

Results The respondents’ mean age was 14.2 ± 2.2 years and 51.3% were females. About 50.7% of all respondents were in senior secondary classes and 50.5% had internet access. Two hundred and sixty (39.8%) had been victims of cyberbullying and 94.3% experienced cyberbullying after school hours. Respondents were often harassed through phone calls (53.2%), in chat rooms (25.2%) and through websites (0.4%). Fifty-two percent of victims reported the incident. Of these 52.7% informed a friend, 28.7% informed a parent/guardian and 1.6% their class teacher. Factors associated with cyberbully victimisation were the respondents’ gender (females more than males), older age, access to internet and being in a senior class. Multiple logistic regression analysis revealed that students with internet access had a higher odds of being victims of cyberbullying (OR = 2.5, CI: = 1.7 – 3.6). Respondents in senior classes also had a higher odds of being victims of cyberbullying (OR = 1.7, CI: = 1.1 – 2.6).

Conclusions The prevalence of cyberbully victimisation was high and students with internet access and those in senior classes were more likely to be victims. Interventions to prevent cyberbullying and improve reporting by victims need to be instituted in schools in the study area in order to curb the problem.