Aims: Facial nerve dysfunction (FND) remains a key postoperative complication of parotidectomy. Intraoperative facial nerve monitoring (IOFNM) aims to assist identification and preservation of the nerve; however, its efficacy remains unclear. This systematic literature review aimed to evaluate whether IOFNM reduces postoperative FND compared with no facial nerve monitoring (NFNM). Methodology: A systematic review was conducted in accordance with PRISMA guidelines. Databases searched included PubMed, Embase, MEDLINE (Ovid) and CINAHL. Studies comparing IOFNM with NFNM during parotidectomy in adult patients were included. Eligible studies reported postoperative facial nerve outcomes using the House-Brackmann (HB) grading system. Retrospective and prospective double-arm studies were analysed. Screening and data extraction were performed independently by multiple reviewers using Covidence. Results: Twelve studies met inclusion criteria. Seven studies demonstrated a statistically significant reduction in immediate or permanent FND with IOFNM (5.13-42.11% with IOFNM vs 12.5-48.3% with NFNM). One study demonstrated a significant difference only in immediate FND (22% with IOFNM vs 74% with NFNM). Four studies showed no significant difference in immediate or permanent FND. Across studies, IOFNM was associated with higher rates of normal postoperative nerve function (HB I), fewer severe paralysis cases (HB III–VI), and faster recovery times. Total parotidectomy carried higher FND risk than superficial procedures; however, IOFNM provided a consistent protective effect across both groups. Conclusion: IOFNM reduces the severity and duration of postoperative FND following parotidectomy but does not eliminate the risk entirely. While evidence supports its protective role, heterogeneity between studies limits definitive conclusions. Standardised monitoring protocols and prospective multicentre trials are needed to determine its optimal application and potential as standard practice. Conflict of Interest: None declared.