Invasive fungal infection remains a major cause of morbidity and mortality in immunocompromised patients. Invasive fungal sinusitis can present as a Tolosa-Hunt syndrome (THS) or orbital apex, leading to frequent misdiagnosis. Accurate diagnosis of fungal infection invading the cavernous sinus or orbital apex is essential to reduce mortality through early antifungal treatment and reduce the risk of worsening with steroid treatment due to misdiagnosis of THS. Herein, we report a case of invasive fungal sinusitis mimicking THS.