Juvenile delinquency in contemporary Nigeria has intensified into a major social problem, marked by the increasing involvement of children and adolescents in violent, organised, and diverse forms of criminal behaviour. This has posed serious threats to public safety and social stability in the country. This study therefore examines the causes and emerging trends of juvenile delinquency in Nigeria, with particular attention to how changing social, economic, and cultural conditions shape youth involvement in delinquent acts. Guided by social learning theory, the study interrogates how family instability, poverty, peer influence, urbanisation, weak social control, and exposure to violence interact to normalise and reproduce delinquent behaviour among young people. A qualitative narrative review design was adopted, drawing on secondary sources including peer-reviewed journal articles, policy documents, institutional reports, and scholarly books published between 2019 and 2024. Thematic content analysis was employed to identify recurring patterns, explanatory frameworks, and areas of convergence and divergence in existing studies. The findings reveal that juvenile delinquency in Nigeria is increasingly diverse, violent, and embedded within broader processes of socio-economic marginalisation, urban stress, and declining moral and institutional regulation. The study concludes that addressing juvenile delinquency requires a shift from punitive responses toward comprehensive social interventions that strengthen families, educational systems, and community structures.