Although a vast amount of researches have been done on the relations of Organizational Citizenship Behavior (OCB) and employees' performance in western or foreign context, there is a little or no empirical evidence in domestic context. However, scholars argue that geographical and cultural differences can bring about differences in OCB. Thus, this empirical study was conducted to find out the relationship between employees' performance and OCB in Ethiopian context, particularly in Dire Dawa. The study was also aimed at investigating the underlying reasons for imperceptibility of OCB in Dire Dawa University. A stratified random sampling technique was used to select 114 employees as the representative sample of the study. The standardized measurement scales were adapted for Liker scale questions and distributed to the employees. Spearman correlation was used to test the co-relational hypotheses while percentage and graphs were employed for the purpose of descriptive analysis. The findings showed that employee's performance is correlated positively and significantly to the OCB dimensions. Furthermore, organizational justice problems and employee's intention to the leave the institution were found to be the major underlying reasons for imperceptibility of OCB among the employees under the study while fairness perception, individual disposition and proper leadership styles, on the other hand, were shown to be the major enabling factors for OCB among employees in the institution's context.