A Dissertation Submitted in Partial Fulfilment of the Requirements for the Degree of Master of Science in Accounting and Finance (Msc A&F) Mzumbe University.This study aimed to examine the impact of corporate tax on firm value and extended to other explanatory variables such as Profitability and Capital structure. A sample of five companies under manufacturing sector was drawn from companies listed in DSE. Those companies are; Tanga Cement, TBL, TCC, TOL and Twiga Cement. The significant of the study was to examine how corporate tax influences the firm value. A time series data for ten years (2007-2016) secondary source were obtained from published financial statements on DSE and companies web sites hence analysed through Regression, descriptive and correlation analysis. It was observed from the findings that, corporate tax has positive relationship and significant on firm value. This means that any additional unit of corporate tax amount has increase impact on firm value. The implication of this result Managers should not evade to pay tax which is prohibited by law instead should be transparency through providing correct information to TRA also this research will help the managers and policy makers to take the rational decisions while evaluating the financial parameters in order to increase the profit and value of the firm. Also policy make should expand the tax bracket by exploiting taxes from foreign direct investment which is current encouraged in our country.