Financial fraud in Nigeria’s oil and gas sector has emerged as a formidable barrier to sustainable economic growth, transparency, and stakeholder confidence. Despite its status as the nation's primary revenue generator, the sector is plagued by sophisticated fraud mechanisms including embezzlement, tax evasion, bribery, money laundering, and fund diversion. Traditional audit frameworks have failed to uncover these illicit activities. Motivated by growing scholarly interest in forensic approaches to fraud detection, this study employed a qualitative methodology guided by the PRISMA framework to investigate the prevalence, patterns, and control strategies related to financial fraud in the oil and gas industry. Through the lens of the Fraud Hexagon Theory, this paper uncovers how systemic governance failures, collusion, and regulatory weaknesses facilitate financial crime. Findings suggest that forensic accounting practices, advanced digital technologies, robust internal controls, and multi-stakeholder collaborations are pivotal for effective fraud detection and prevention. Recommendations call for institutional reforms, compulsory forensic audits, and capacity building