Purpose—This paper investigates the role of forensic accounting skills in enhancing auditor self-efficacy towards fraud detection in Indonesia. It also examines the moderating effect of the implementation of Generalized Audit Software (GAS) and the whistleblowing system on the relationship between accounting and auditing skills and auditor self-efficacy, as well as their combined role in enhancing fraud detection. Methodology—A cross-sectional survey was conducted with 537 external auditors in Indonesia. Data were analyzed using multiple linear regression with moderation models, employing WarpPLS 8.0 software. Findings—The results indicate that practical communication skills, psychosocial skills, and accounting and auditing skills significantly enhance auditor self-efficacy. However, technical and analytical skills do not show a significant effect on auditor self-efficacy. Furthermore, auditor self-efficacy is found to have a direct and significant impact on fraud detection. This study also reveals that implementing GAS moderates the relationship between auditor self-efficacy and fraud detection, whereas the whistleblowing system does not demonstrate a significant moderating effect. Novelty—This study contributes to the literature by highlighting the role of forensic accounting skills and the implementation of GAS in enhancing auditor self-efficacy and fraud detection in the Indonesian auditing context.