The purpose of this study is to explain the mediating role of organizational citizenship behavior in the relationship between personality and public service motivation towards employee job performance. The study focused on employees of Gondar city administration public organizations relationship of Job performance with personality, public service motivation, and organizational citizenship behavior in order to ensure organizational effectiveness, efficiency and relevance. This study is Explanatory research and quantitative research approach. For theoretical and empirical data collection, this study used secondary data and primary data by using quantitative research approach. . Five scale Likert-type questionnaires were constructed and distributed for 376 study participants selected through probability sampling method among 6198 population. The data analysis performed by using SPSS V 23 statistical software, Andrew Hayes process macro and Sobel test. The multiple regression model used to analyze the data and to examine the mediating effect of organizational citizenship behavior in the relationship between personality and public service motivation with job performance In the case of Gondar City public servants. The regression result reveals that Personality, and public service motivation are significant determinants of employees’ job performance. Moreover organization citizenship mediates the job Based on result concluded that personality and public service motivation are key elements to promote job performance and service delivery to the public, and enable to build social trust and good governance.