This study investigated the influence of supervision of pre-teaching activities on teacher's competence in primary schools in Kanungu District, South Western Uganda. To achieve the purpose of the study, a null hypothesis was formulated. Cross – sectional research design was used for the study. Purposive sampling was used to identify head teachers and SMC, while simple random sampling was used to select teachers and student leaders. Content validity of the instruments was established by subjecting the instruments to the scrutiny of research experts and the instruments refined at their recommendations. Questionnaires further subjected to rating and Content Validity Index (CVI) of 0.974 and 0.939 obtained for the teachers’ and students’ questionnaires respectively. To determine reliability of the instruments, Cronboch’s alpha reliability coefficient was computed for each set of questionnaires using SPSS (Version 25) and Cronboch’s alpha value of 0.956 and 0.865 obtained respectively, confirming that the instruments were reliable in achieving the objectives of the study. Data collection was carried out using interviews and questionnaire survey. Descriptive statistical Analysis with frequencies and percentages was used to analyze quantitative data and Pearson Product Moment Correlation co-efficient (r) was used to establish the direction and strength of relationship between supervision and teacher's competence at 0.05 level of significance. Results obtained revealed that supervision of pre-teaching activities has a significant positive relationship with teacher's competence; also supervision of pre-teaching activities has a significant positive influence on teacher's competence in primary schools. The study concluded that supervision of pre-teaching activities has weak but significant positive influence on teacher's competence. The study recommended that supervision be carried out alongside improvement in working conditions to create job satisfaction for teachers for better competence.