Past studies endorsed that quite a several factors have been considered as the influencing factors of performance in an organization. These are commitment, personality, emotional intelligence, organizational support, leadership, and organizational citizenship behavior. While some studies considered investigating the influence of human resource management practices on organizational performance in contexts such as America, Asia and Europe, very little attention has been given to sub-Saharan African countries like Nigeria. Thus, this manuscript attempted to investigate the impact of the compensation system, training and development on organizational performance through mediation effect of ethical climate using quantitative analysis. To examine the relationships, a survey was conducted using 181 respondents from Nigerian educational sector administration (ministries, parastatals, agencies and boards). The data was analyzed, and hypotheses were tested using Smart PLS SEM 3.2.6. The study found that ethical climate fully mediates the relationship between the compensation system, training & development and organizational performance. Therefore, this research recommended a sincere need to implement a better compensation system and offer adequate training and development by the management in the educational sector to employees, which will ensure their superior performance as well as organizational performance, more specifically in Nigeria's educational sector administration. Keywords: Organizational performance, compensation system, training and development, ethical climate, PLS-SEM.