The current wave of unrest among secondary schools students in Kenya is an indication of a serious problem in schools related to juvenile delinquency behaviours. For over two decades, this has been undermining the adolescents’ achievement and development. In this regard, juvenile delinquent behaviours have far reaching consequences; hence the present study sought to explore into the relationship between students’ indulgence in various delinquency behaviours and their academic achievement in Mumias sub-county, Kakemega County, Kenya. Specific objective for the study was to determine the elements of delinquent behaviours among secondary students. The study adopts Jessor's Problem Behaviour Theory (PBT) and ex post facto research design to explain the various study variables. The target population of this study was 54 secondary school deputy principals, 54 guidance and counselling teachers, 218 class teachers, 7548 form two and three students. The sample of the study consisted of 47 secondary school deputy principals, 47 guidance and counselling teachers, 139 class teachers and 365 form two and three students. Data was collected using questionnaire, observation schedules, interview schedules and document analysis.