Embracing and managing diversity in today’s business world is an essential part of successful business practices as it brings various voices to a team, improves morale and increases overall productivity. However, manager face difficulties in understanding the value of each person’s unique abilities or voice, there may arise some instances where certain employees still have conflicts. Ineffective communication of key objectives results in confusion, lack of teamwork, and low morale. In the office of the attorney general and department of justice now going through a massive influx of young workforce in both gender with diverse educational background and from different ethnic groups have brought a challenge of having different sets of values, expectations, and work styles in the work place and also understanding the other’s culture has been a heavy task on managing work force in the organization. It is due to this regard that this study sought to investigate the influence of workforce diversity on employee performance in the office of the Attorney General and Department of Justice in Nairobi City County, Kenya. The study specific objectives were to examine the influence of educational background diversity, ethnicity diversity, age diversity and gender diversity on employee performance. The theories guiding the study were the human capital theory, social identity theory, social exchange theory and social categorization theory. This study will use descriptive survey research design. The unit of observation was office of the Attorney General and Department of Justice in Nairobi City County, Kenya and the unit of observation was 5 Human Resource Managers and 50 Support Staff from HRM department. A census of 55 respondents was carried out. Primary data was collected using questionnaires. Quantitative data was analysed with the use of descriptive statistics such as mean and standard deviations and presented using tables, graphs, charts and figures. Content analysis was used to test data that was qualitative in nature or aspect of the data collected from the open ended questions. Multiple regression analysis was used to test the extent to which the variables relate to each other. The study examined that educational background diversity, ethnicity diversity, age diversity and gender had a positive and significant relationship on employee performance. The study concluded that employees with diverse educational background promote higher levels of consistency, creativity because of their unique perspectives. Ethnicity diversity management improve gains in worker welfare and efficiency, leads to reduced turnover costs, fewer internal disputes and grievances, prevention of marginalization and exclusion of categories of workers, improved social cohesion and so on. Age diversity in the workplace provides a larger spectrum of knowledge, values, and preferences. Having a diverse gender within the organization leads to a wider talent pool, encourages different points of view and approaches that come from different life experiences and the organization to challenge gender stereotypes. The study recommended that the organization should employ people of different backgrounds in education so as to improve creativity and innovation. The organizational management has responsibilities when it comes to promoting and monitoring ethnic diversity policy in the workplace. It is highly essential for the organization to find effective ways to meet the challenges of age diversity because both the old and the young employees can make tremendous contributions to the organization, in their own unique way. The organization should encourage team leaders to select diverse groups for projects to ensure the genders do not naturally separate.