Background: Mucoepidermoid carcinoma (MEC) is the most common malignant salivary gland tumor, representing approximately 30–35% of all salivary gland malignancies. Primary intraosseous MEC of the jaws is an exceptionally rare entity, with fewer than 200 cases reported in the literature since its first description in 1939. Its clinical presentation is often nonspecific, contributing to delayed diagnosis and potential mismanagement. Objective: To highlight the diagnostic challenges and clinical significance of atypical presentations of intraosseous mandibular MEC, particularly those associated with neurological manifestations. Materials and Methods: We report a case of primary intraosseous MEC of the mandible with unusual clinical features, emphasizing the diagnostic process, radiological and histopathological findings and therapeutic management. Results: Intraosseous MEC typically presents as a slow-growing, painless swelling in the posterior mandible, often mimicking benign odontogenic lesions. Neurological symptoms are uncommon and usually limited to inferior alveolar nerve involvement, presenting as hypoesthesia or paresthesia. In this case, the presence of facial nerve palsy as an initial symptom represented a rare and alarming feature, suggesting advanced disease or neural invasion. Imaging and histopathological examination confirmed the diagnosis, guiding appropriate surgical management. Conclusion: Intraosseous MEC of the mandible remains a diagnostic challenge due to its rarity and nonspecific clinical presentation. The occurrence of facial nerve palsy as an initial manifestation is exceedingly rare and should raise suspicion for aggressive disease. Early recognition and comprehensive evaluation are essential to ensure accurate diagnosis and optimal management.