A Research Report Submitted to Mzumbe University – Mbeya Campus College in Partial Fulfillment of Requirements for Award of Bachelor Degree of Laws (LL.B) of Mzumbe UniversityThe study aimed at investigating the “The tax avoidance in Mainland Tanzania: The Law and Practice of Modern Anti-Avoidance Provisions under the Tax administration Act, Cap. 438 R.E 2019.” In the statement of the problem explained that tax avoidance is everlasting existence of tax avoidance schemes in Mainland Tanzania. Tax avoidance is not liable to be punishable in law and whenever the practice is being detected by tax authorities, in other words tax avoidance has been acknowledge that a taxpayer has right to plan his or her affairs within the law so as to avoid paying tax. The specific objectives of this research were; to examine the effectiveness of general and specific anti-avoidance provisions and to examine fairness of tax administrators, justification of tax laws, accountability of the government, and how multiplicity of taxes encourages tax avoidance. The researcher managed to use both primary and secondary data whereas primary data was obtained through questionnaire survey and oral interviews. The researcher used purposive sampling method was adopted to pick questionnaires to respondents who were the employees of Tanzania Revenue Authority (TRA) at Kahama district within Shinyanga, these employees were who were, tax assessors, accountant, and advocates specialized in tax law. The researcher also used random sampling to trap information about tax avoidance schemes from taxpayers of Kahama district. The secondary data was obtained through documentary review and online accessed materials. The finding of the study revealed that to some extent the modern anti-avoidance provisions under the Tax Administration Act (TAA), Cap.438 R.E 2019 are effective in curbing tax avoidance schemes in Mainland Tanzania. Based on the findings, the researcher recommended that, the Income Tax Act, Cap. 332 R.E 2019 should be amended so as to avoid all loopholes which attracts tax avoidance schemes to be practiced in Mainland Tanzania; Tanzania government should form tax-related agreement with tax heaven countries so as to end tax avoidance schemes; and researcher also recommended that the TRA should review tax rates which will be affordable to taxpayers.