The study is to establish the effect of Examiners’ personality and effectiveness on conveyor belt system of marking in Uganda that looked at Namungoona High Secondary School as a case reference. The study was guided by three specific objectives, that are; to examine the effect of Examiners’ attitudes on effectiveness of conveyor belt system of marking, to establish the effect of Examiners’ values on effectiveness of conveyor belt system of marking and, to assess the effect of Examiners’ beliefs on effectiveness of conveyor belt system of marking. This research used a descriptive correlational research design to describe the effect of Examiners’ personality on effectiveness of conveyor belt system of marking. The study used a research population of 260 and a sample size. From the findings, the linear regression results shown that the correlation between examiners’ attitudes and effectiveness of conveyor belt system of marking was positive and significant. The regression coefficient for examiners’ attitudes and effectiveness of conveyor belt system of marking was 0.264, indicating that for every one-unit increase in examiners’ attitudes would on average led to 0.264 increases in effectiveness of conveyor belt system of marking.