Increase in the use of the Internet by adolescents, though beneficial, has become an ample means to their risk exposure. There is a dearth of information on how parental mediation and children’s risky Internet behaviours jointly influence adolescent Internet risk exposure, particularly in Africa. The present study, therefore, investigates the influence of parental mediation and adolescents’ Internet behaviors on Internet risk exposure of students in selected private, state and federal secondary schools in Oyo State, Nigeria. Using the survey research method, a structured questionnaire adapted from three previous studies was constructed and used for data collection. Three hundred copies of the questionnaire were administered among students, out of which two hundred and thirty nine (239) were retrieved. Using the Statistical Package for the Social Sciences Version 23, descriptive and inferential analyses were performed. It was found that none of the parental mediation strategies had a significant negative effect on children’s Internet risk exposure while some students’ behaviours and characteristics had significant positive effects on risk exposure. The study recommends, among others, that stakeholders in education and technology sectors should attend to Internet safety needs of these secondary school students.