This study was carried out on the need to provide empirical evidences and establish the relationship existing between teachers' attitude and students' achievement as well as the relationship between teacher-student and students' academic achievement in agricultural science in Abia State, Nigeria. Two specific objectives guided the study. Two research questions as well as two null hypotheses were formulated and tested at 0.05 level of significance. The study adopted correlational study design. The study was carried out in Abia state. The population of the study was 9,963 consisting of 9,690 students and 273 teachers of agricultural science (Abia State Secondary Education Management Board, 2020). The sample size of 330 respondents consisting of 30 teachers and 300 students were selected and used for the study. A multistage sampling (simple random-purposive-simple random) procedure was adopted for this study. The study made use of two instruments for data collection; a questionnaire titled; Teacher Relationship and Attitude Questionnaire (TRAQ) structured on 4-point scale of 4=Highly Utilized (HU), 3=Utilized (U), 2=Averagely Utilized (AU) and 1=Not Utilized (NU) and a standardized agricultural science achievement test (AAT) adapted from 2018 WAEC agricultural science paper 2. The instruments were validated by three experts, two from the Department of Agricultural/Home-science Education and one from Department of Measurement and Evaluation in College of Education, Michael Okpara University of Agriculture, Umudike. The reliability of the instrument for the study was determined using split-half method of reliability which gave a reliability coefficient of 0.82 and 0.88 for the two instruments respectively. 330 Copies of TRAQ and AAT were administered to the respondents but 312 copies of the administered instruments were retrieved representing 94.5% retrieval rate. The data collected were analyzed using Pearson Product Moment Correlation to answer research questions and linear regression to test the hypotheses at 0.05 level of significance. Based on the findings, it was recommended among others that teachers should know that their relationship with their students plays a vital role in the students' achievement. As a result, they should always create a good relationship with their students. Positive and negative reinforcement should only be utilized when and where necessary.