The motivation of public managers to provide accurate personnel performance appraisals in the public sector is an unexplored area of study in public administration. This study provides preliminary steps in developing a rater motivation model (RMM) for the public administration field. The RMM is built using three primary determinants of rater motivation (felt accountability, incentive structures, and public service motivation). In addition, this study examines the variations in raters’ perceived rating accuracy depending on the existence of a reward system for accurate appraisers and an organizational forced distribution rating system. The sample consists of public officials working in various levels of the U.S. and Korean governments. This study uses confirmatory factor analysis to construct measures of rater motivation and multiple regression analysis to observe the relationship between the determinants and the rater’s perceived performance rating accuracy. The findings suggest that raters are significantly affected by all three determinants of rater motivation as well as by the presence of rewards for accurate appraisal and a forced distribution rating system. Implications for both the public administration literature and practice are suggested.