Efficiency and productivity of human resource depends upon many factors including motivation. The study aimed at determining the effects of motivation upon public primary school-teachers’ work performance. The following three objectives guided the study: to identify kinds of motivations addressed to public primary school teachers; to find out whether or not public primary school-teachers’ are motivated in their performance; and to determine the effects of motivation upon public primary school-teachers’ work performance. The literature review section addresses motivation strategies, effects of motivation and the theory of Maslow’s hierarchy of needs guiding the study because it emphasizes on the idea that, motivation is based on a hierarchy of needs, by which a person cannot move to the next level of needs without satisfying the previous level. The research methodological section is based on the triangulation design employing interviews among primary school heads and DEO while questionnaires were for primary school teachers forming a sample size of 102 respondents sampled using both purposive and simple random sampling techniques respectively. The study revealed both positive and negative effects of motivation among primary school teachers. It was found that, 96 (100%) teachers mentioned improving productivity to be among the positive effects of motivation among teachers, 96 (100%) teachers mentioned lowering teachers’ absenteeism, 96 (100%) teachers listed increasing working morale and 86 (90%) teachers proposed lowering the rate of teachers’ turnover. The vice versa is true for negative effects. However, if negative effects overweight positive effects performance among xiii primary school teachers may also negatively be affected leading to poor students’ achievement. The researcher recommends that the issue of motivation should start at school level whereby head-teachers ought to motivate teachers performing well in their daily responsibilities. Hence, managerial behavior should be motivating or satisfying to the extent of increasing goal attainment by subordinates and clarifying the paths to those goals so as to enhance commitment among teachers. Conclusively, the government as an employer should ensure that all problems associated with teachers’ motivations are dealt with high effort and on time, this is because delaying them discourages workers including teachers in their work performance.