Shorttitle: Violent behaviour has become a concern in the Kenyan educational system. It is manifested in the form of rioting, sexual violence and bullying. This contributes to physical disability and poor academic performance in schools. In Western Province, cases of student violence in secondary schools have been reported in the recent years. For instance, in 2008, eight cases were reported, whereas in 2009 the number rose to over 30 cases. The purpose of the study was to establish teachers'' and students'' perceptions of factors contributing to violent behavior among public secondary school students in Western Province, Kenya. Objectives of the study were to: establish teachers'' and students'' perceptions of forms of violence; and identify home, psychological, school and physiological factors contributing to violent behaviour. The study was based on the Social learning theory by Albert Bandura. A descriptive survey research design was adopted. The study population was composed of 638 Principals, 6,354 teachers,65,969 form two students and 21 District Education Officers.