The paper takes a cursory look at the management of students' ethical behaviour and discipline in public senior secondary schools in Lagos State, Nigeria. It highlights the crucial role of teachers in moulding students' character and fostering a positive school environment. The paper also sheds light on effective strategies for managing students' ethical behaviour and promoting discipline in the classroom. The paper concludes that management of students' ethical behaviour significantly impacts discipline in public senior secondary schools in Lagos State, Nigeria. By setting clear expectations, building positive relationships, modelling ethical behaviour and implementing restorative practices, teachers can effectively manage students' ethical behaviour. It is then recommended that clear code of conduct should be made accessible to teachers, students and parents; teachers should be provided with regular development training; guidance and counselling services should be made available for students struggling with ethical issues as well as communicating with parents on issues concerning their children.