This paper explores the teaching profession and the impact of teachers' conduct on the academic performance of students. It noted that as teaching is one of the oldest and well respected professions in the world, the role of the teacher in the effective delivery of knowledge and in bringing about a conducive atmosphere for learning cannot be over emphasized. The paper examines the conduct of teachers in line with the expected professional conduct as enshrined in the constitution of the Teachers Registration Council of Nigeria. It emphasized that there are certain ways by which teachers' conduct, styles and attitudes impact negatively on the academic performance of the students. Some examples include their dressing, quality/qualification, communication and teaching style, guidance, effect of their instructional resources, discipline and motivation. Lastly, the paper advocated for student centered teaching where skills acquisition and learning for life is encouraged, and memorizing de-emphasized. Furthermore, the strategies for teachers' relationship with the learners as expected in the 21st century and the counselling implications of their misconduct were also discussed.