This study examined the application of ChatGPT in the Nigerian educational system with particular attention to its ethical concerns, barriers and strategies for effective application. ChatGPT has emerged as a widely used generative artificial intelligence tool that supports teaching, learning, academic writing, lesson preparation, assessment development and research activities in universities, colleges of education, polytechnics and other tertiary institutions. Students use the technology for independent learning, assignment preparation, examination revision and academic writing, while lecturers employ it to develop instructional materials, generate classroom exercises and support curriculum delivery. Despite these educational benefits, the study identified several ethical and institutional concerns associated with its adoption. Major ethical issues include plagiarism, academic dishonesty, fabrication of references, misinformation, algorithmic bias, privacy and data protection challenges, and excessive dependence on AI-generated content. The review also revealed important barriers affecting effective implementation in Nigeria, including inadequate digital infrastructure, unstable electricity supply, poor internet connectivity, limited artificial intelligence literacy among lecturers and students, insufficient institutional policies, resistance to technological change and concerns regarding the reliability of AI-generated information. These challenges have implications for academic integrity, critical thinking, independent learning and educational quality. To promote responsible application, the study recommends the development of comprehensive national and institutional AI policies, continuous professional development for educators, AI literacy programmes for students, improved digital infrastructure, stronger academic integrity regulations, verification of AI-generated information using credible scholarly sources and the redesign of assessment methods to promote originality and higher-order thinking. The study concludes that ChatGPT should function as a complementary educational resource rather than a substitute for lecturers, independent scholarship or established academic practices. Its successful integration depends on ethical governance, institutional preparedness and continuous evaluation of emerging artificial intelligence technologies.