A Research Report Submitted to the School of Business in Partial Fulfillment for the Requirement for the Award of the Bachelor of Accounting and Finance in Business Sector (BAF-BS) of Mzumbe University.The study was conducted at Tanzania Revenue Authority (TRA) – Mwanza Tax region office with the focus on assessing the Determinants of Tax Evasion in Tanzania. The objective was to examine the influence of demographic determinants on Tax evasion, determine the influence of demographic determinants on Tax evasion, to determine the influence of demographic determinants on Tax evasion The study employed Explanatory study design; the target population was TRA staff. But the main focuses were staffs from department of domestic revenue and compliance unit. Purposive/judgmental sampling technique was used to select a sample of 20 TRA staffs. In this study data was collected using questionnaire and interview methods of data collection. The study findings regarding, analysis shows that non-economic determinants have the strongest impact on tax evasion in comparison with economic determinants. These various determinants into mixed models of tax evasion, our understanding is enhanced about tax evasion. Complexity of tax laws is found to be the most important determinant of tax evasion. Other significant determinants are education, income source, fairness and tax morale. The results, show that the lower the level of complexity of tax laws and the higher the level of general education, services income source, fairness and tax morale, the lower the level of tax evasion across. The results have implications for governments that seek to reduce the level of tax evasion in society. A simple tax system can reduce tax evasion. Recommendations were given by the researcher to the TRA office at Mwanza must enhance strong block management system as a strategy to identify eligible traders who are supposed to be in the VAT system and all other traders who are conducting business but do not pay tax be registered. This can be possible through employing qualify, trained and motivated personnel with an investigative mind so as to attain desired output. This will create good atmosphere of fair competition among the business community, hence enhances revenue generation. TRA office in Mwanza together with the recommendation mention above should use stiff punishment for those who practice this act of tax evasion once they are being identified according to the law and register them as the Tax Laws stipulates