This research article discusses the impact of teacher's behaviour on the academic achievement of university students. All the teachers and students of public sector universities constituted the population. From the 15 public sector universities, 375 teachers and 1500 students from five departments were selected as a sample. Two questionnaires were developed and validated through pilot testing and administered to the sample for the collection of data. The researcher personally visited respondents, thus 100% data were collected. The collected data were tabulated and analyzed by using chi-square and Pearson's product moment coefficient of correlation (r). The major conclusions of the study were that teachers felt proud to be teachers, they adjusted themselves with the prevailing situation and circumstances, and they used different motivational techniques for teaching. Students were found to be satisfied with the positive behaviour of their teachers. The relationship between the teachers' behaviour and corresponding academic achievement (marks) revealed a highly positive significant correlation. (Contains 2 tables.)