Frequent occurrences of fraud take place due to poor fraud prevention and detection. The purpose of this study is to ascertain the impact of internal audit effectiveness and continued professional commitment to fraud detection with internal auditors’ quality as a moderating variable. Seventy-eight questionnaires were distributed to internal auditors and supervisors at the Inspectorate of Riau City, Indonesia, who had at least two years of experience. Structural equation modeling (SEM) 3.0 software was used for the data analysis. According to the study’s findings, the effectiveness of internal control (β = –0.932; p < 0.05) and the effectiveness of internal auditors (β = 1.149; p < 0.05) both have an impact on fraud detection. However, ongoing professional commitment (β = 0.069; p > 0.05) has no impact. Quality of internal auditors does not affect the relationship between the effectiveness of internal audits (β = –0.190; p > 0.05), the effectiveness of internal control (β = 0.114; p > 0.05), continued professional commitment (β = 0.018; p > 0.05), and fraud detection. The findings of this study can be used as guidance for management to enhance the performance of internal auditors and for considerations and assessments for fraud detection in the public sector.