The research study focused on teachers’ perceptions on the classroom observation of Quality Assurance Officers in improving performance of Certificate of Secondary Educational Examination (CSEE) in Mwanga district. The study was anchored by expectancy theory by Lewin and Tolman in 1932. The study employed quantitative approach whereby cross-sectional survey design. the target population was 24 heads of schools, 412 teachers from 24 public secondary school in Mwanga district and 7 Quality Assurance Officers. Sample random and stratified sampling technics were used to get 5 Quality Assurance Officers, 8 heads of schools and 82 secondary school teachers to make a sample size of 95 participants. Validation of instruments was done by two research experts from MWECAU. Questionnaires were used to collect data from teachers and interview schedule to heads of schools and Quality Assurance Officers. The data were analyzed quantitatively using descriptive statistics. Before actual data analysis, a pilot study was conducted to establish the reliability of data through Cronbach Alpha (r=0.71 for teachers’ questionnaire data). The finding revealed that 3.083 mean percentage of teachers indicated that Quality Assurance Officers conduct their classroom observation role in assessing content delivery, teaching and learning methods, availability of teaching and learning documents, preparation of teaching documents for improving students’ performance in CSEE. However, it was indicated that various factors influenced teachers’ perceptions with most noticeable one of being past experiences of teachers to Quality Assurance Officers. The study concluded that 3.083 mean score of teachers in Mwanga district have positive perceptions on classroom observation by Assurance Officers. However, it was also concluded that some teachers still take Quality Assurance Officers as fault finding people due to factors like past experiences with school inspectors. The study recommended that conducting frequent school visit, using friendly, respectful communications with teachers will improved the perceptions of teachers. But also, Quality Assurance Officers should have a regular follow up mechanisms in order to ensure that their feedback report is implemented as expected.