A Dissertation Submitted in Partial Fulfillment of the Requirements for Award of the Masters of Science of Human Resource (MSc-HRM) of Mzumbe UniversityThe study is about the The study aimed at investigating the assessment of workplace diversity on demographic, social-culture, its management and how does it impact organization performance at TPA as a case study. The study has the following specific objectives, to evaluate the magnitude of demographic workplace diversity of employees in TPA, to evaluate the extent of organizational- social-cultural workplace diversity of employees in TPA, to examine how the workplace diversity management is implemented at TPA, to determine the impact of workplace diversity management on the organizational performance in TPA. The Research methodology concerned about data collection where the researcher applied systematic approaches in data collection. Both qualitative and quantitative were used to the 92 respondents from TPA. Closed and open ended questions was used where the collected data were coded and analyzed by using Statistical Package for social Science (SPSS) and Microsoft excel where table and figures were drawn. Results of the analysis showed that, the management and employee from TPA knows the importance of workforce diversity and the work force diversity play a great role in the workplace.Today’s workforce is a reflection of the considerable mix of cultures, ages, religions, and races. Mostly influence workforce diversity at TPA was physical ability and ethnicity, where by diversity includes cultural factors such as race, gender, age, colour, physical ability, ethnicity. People of different ethnic backgrounds possess different attitudes and values. Language in among Tanzania tribes is related to the ethnic background. TPA the performance has increased because of neglecting gender biasness The management of TPA is advised to establish unit which will conduct the assessment of the work performance as results of workforce diversity, the unit should prepared all material respects in accordance with an identified and reporting the performance i.e. give true and fair view, and advice to the management on matters involving day to day-as far as workplace diversity is concern. The TPA should provide training and education on newly launched/adopted employee, and important of workplace diversity. This will make employees comfortable, efficient and effective in their works