ABSTRACT
The study addressed the factors contributing to the effectiveness of internal audit functions in the public sector. The specific objectives were to identify practices that influence the effectiveness of the Internal audit in TTCL, to examine the relationship between the competence of internal audit staff and the effectiveness of the internal audit function in TTCL, to examine the relationship between the independence of internal audit and effectiveness of the internal audit unit in TTCL. The study population consisted of 70 out of 100 individuals, from which the study's sample was drawn. A questionnaire and interview were used to gather firsthand information from the respondents, including their gender, age, level of education, and work experience, and the data was analyzed using SPSS. 
Based on the findings of the regression analysis, the audit competency of the internal auditors, independence and objectivity of internal audits, and practice to the effectiveness of internal audits were strong predictors of the effectiveness of the internal audit function. The findings indicate that 55 respondents (80.3%) agree that the capacity and quality of internal audit contributes to the effectiveness of the internal audit function of the Tanzania Telecommunications Corporation (TTCL). In addition, 27 respondents (89.9%) agreed with the independence and objectivity of the internal audit.
Regarding the internal auditor's practices and the value of internal audit, 62 respondents (87.9%) agreed with its contribution. Regression analysis shows that " internal auditors practices and value of internal audit" is a strong predictor of "effectiveness of the internal audit function" (B=0.249, 0.526, 0.061). These results demonstrate a positive outlook on the effectiveness of the internal audit function in Tanzania Telecommunications Corporation. The study concludes that the internal auditing function influences the growth of parastatal organizations in Tanzania. Also, Governments should promptly upgrade their systems to encourage internal audit staff to use computer-based auditing techniques.