Fungal sinusitis is uncommon and can be classified into noninvasive and invasive types. Noninvasive forms include the sinonasal fungus ball (SNFB) and allergic fungal rhinosinusitis (AFRS), both of which occur in immunocompetent patients. SNFB presents unilaterally, often in the elderly, and is treated primarily with nonurgent surgery. AFRS involves type I hypersensitivity to fungi, presents in younger patients, and is treated with a combination of surgery and medical therapy. Invasive fungal sinusitis, including acute and chronic types, affects immunocompromised individuals and requires urgent intervention. Diagnosis involves imaging and biopsy, with treatment combining surgery, antifungal therapy, and immune status management.