The importance of Internal Audit in an organisation cannot be over emphasised. Decisions made by organisations are very crucial to the progress of the organisations. Due to lack of necessary internal audit procedures, organisations have become ineffective and Unprofitable. In the light of this problem, this study examined, the role of internal audit in enhancing transparency in public firms in Nigeria. The population of this study consists of the staffs of five selected public firms listed in Nigeria stock Exchange. The data for this research were gotten from questionnaires administered and collected from 50 respondents. Data generated for the study were analysed andtranslated using frequencies and percentages. The hypotheses were tested using regression analysis at 5 per cent level of significance (0.05). The outcome of the analysis showed that Internal Audit has positive and significant effect on Fraud prevention in Nigeria Public Firms.The R2of 0.554 indicates that 55.4% of the variations in fraud prevention are due to internal audit. From the result, Internal Audit also has positive and significant effect on Firm Credibility in Nigeria Public Firms. The R2 of 0.478 indicates that47.8% of the variations in Firm Credibility are due to Internal Audit. Finally, the result indicated that internal audit has a positive and significanton Corporate Governance in Nigeria Public Firms. Based on the findings, it was concluded that internal audit has a great role to play in enhancing transparency in Nigeria public firms. We then recommend that proper internal audit department must be established and that management of organizations should co-operate with internal audit staff to prevent fraud and increase the credibility of the organizations.