Osteomyelitis is an infection involving the bone and bone marrow, most commonly caused by bacterial pathogens, though it can rarely occur due to fungal organisms. Candida glabrata is a Candida species that is challenging to treat because of its inherent resistance to azoles. Fungal osteomyelitis of the mandible is exceedingly uncommon, and infection with C. glabrata at this sites has not been previously reported. This report describes an unusual case of mandibular osteomyelitis that developed following a dental procedure, with C. glabrata identified as the pathogen. A 36-year-old man with diabetes mellitus presented with painful swelling extending to the face and neck after undergoing root canal treatment on his right lower molar. Despite receiving antibiotics, his symptoms persisted, and contrast-enhanced magnetic resonance imaging (MRI) confirmed mandibular osteomyelitis with abscess formation. C. glabrata was isolated from tissue obtained during surgical debridement, and antifungal susceptibility testing was performed. The patient received intravenous caspofungin for 6 weeks, followed by oral fluconazole to complete a 6-month total treatment course once clinical improvement was noted. The patient demonstrated clear clinical and radiological improvement. This case highlights that fungal pathogens should be included in the differential diagnosis of infections occurring after dental procedures that do not respond to antibiotics. Selecting an appropriate antifungal agent and performing timely surgical management are essential for successful treatment