AJIBOYE, Samuel KolawoleANYANWU, FrancisSAIDU, Abubakar2021-06-082021-06-082019https://uilspace.unilorin.edu.ng/handle/20.500.12484/6049Delinquent behaviour among students is one of the major factors militating against smooth teaching and learning in schools. This study investigated causes of delinquent behaviour among in-school adolescents as perceived by teachers in Kwara State, Nigeria. The study adopted the descriptive survey research design. The target population consisted selected secondary school teachers in Kwara State. Purposive and simple random sampling techniques were used to select 384 respondents. The research instrument used was a questionnaire entitled “Causes of Delinquent Behaviour Questionnaire”. Having been subjected to test re-test method and the Pearson’s Moment Correlation Coefficient formula the instrument possessed a reliability coefficient of 0.87. The descriptive and inferential statistics were used to analyse the data. The findings revealed that the major causes of delinquent behaviour among in-school adolescents as perceived by teachers are poor study habit, negative peer influence in school and poor school classroom condition. No significant difference in causes of delinquent behaviour among in-school adolescents as perceived by teachers based on gender and work experience. It was recommended, among others, that students should be enlightened on how to develop good study habit and both the school (teachers, guidance counsellors and others.) and home should synergise to ensure monitoring of peer activities of in-school adolescents.enDelinquent BehaviourIn-school adolescentsCauses.Article