Purpose: To report a case of orbital apex syndrome resulting from invasive fungal sinusitis attributed to the unusual <i>Candida glabrata</i> species.Case summary: A 76-year-old patient presented with persistent left-sided orbital pain, headaches, and blurred vision for 3 weeks. The patient had a history of uncontrolled diabetes, chronic kidney failure, and angina, and was treated for a COVID-19 infection 1 month prior to admission. Contrast-enhanced computed tomography scans revealed extensive bilateral sinusitis affecting the left optic nerve. The patient underwent endoscopic sinus surgery, which included nasal cavity biopsy, conducted by an otorhinolaryngologist. Histopathological analysis using Gömöri methenamine silver stains identified <i>Candida</i>. Cultures from sinus specimens later grew <i>Candida glabrata</i>. Treatment involved daily IV amphotericin B followed by oral itraconazole. After 6 months, the patient fully recovered from fungal sinusitis but continued to experience negative light perception in the left eye and progressed to complete ophthalmoplegia, consistent with orbital apex syndrome.Conclusions: Reports of invasive fungal sinusitis caused by <i>Candida</i> infections are rare globally. This report marks the first occurrence in this country. Effective management requires careful assessment and appropriate treatment tailored to the specific species, especially considering the risk of orbital extension of the inflammatory lesion.