Odontogenic keratocysts (OKCs) in the maxilla are rare. Although destructive, their clinical presentation can mimic inflammatory conditions like radicular cysts and osteomyelitis. OKCs originate primarily from odontogenic sources. On radiography, they present a unilocular to multilocular radiolucency and may involve the maxillary sinus. Enucleation with chemical cauterization is the best treatment for limiting cyst recurrence. However, superaided infections, such as fungal sinusitis, can adversely affect the condition and require a more comprehensive treatment plan. The present case report describes an OKC of the upper jaw involving the maxillary sinus in a 42-year-old male with a superadded fungal infection. The treatment plan included enucleation with chemical cauterization along with inferior meatal antrostomy. In addition, an antifungal protocol was instituted. A follow-up period of one year was not associated with any complications.