This study examined the relationship between internal auditing and fraud prevention at Metropolitan International University (MIU), Uganda. Fraud poses a serious threat to the financial health, reputation, and sustainability of organizations, and internal auditing is widely regarded as a key line of defence against it. The study investigated how audit independence, the internal control system, risk assessment, and audit competence relate to fraud prevention. A cross-sectional survey design with a mixed-methods approach was adopted, and data were collected from 150 respondents comprising management, accounting and finance staff, internal auditors, and administrative staff using structured questionnaires and interviews. Descriptive statistics, Pearson correlation, and structural (path) analysis were used. The results revealed a strong positive and significant relationship between internal auditing and fraud prevention (r = 0.68, p < 0.01), with the internal auditing dimensions jointly explaining 66.0% of the variance in fraud prevention (R² = 0.660). The internal control system (β = 0.32) and audit independence (β = 0.30) emerged as the strongest path predictors. The study concludes that effective internal auditing significantly enhances fraud prevention and recommends strengthening the internal control system, safeguarding auditor independence, and building audit competence.