The aim of this paper is examining the effect of diversity management on organizational performance by focusing on Ethio-Telecom (Ethiopian Telecommunication) South West region offices. Using Survey research design a quantitative data was randomly collected from a total of 120 employees. Path analysis was conducted to test the three research hypothesis. The result of empirical analysis showed that organizational diversity management constructs or dimensions (ethnicity, gender, and religion) are positively related with organizational performance. Hence, diversity management can positively influence employee productivity, satisfaction, creativity and innovation and better decision making there by fostering organizational performance.