The maxillary sinus is the first sinus to develop in the human fetus and continues growing until puberty. Maxillary sinus aplasia is a rare condition characterized by the failure of sinus development. A 61-year-old female was referred to the otolaryngology clinic by a maxillofacial surgeon due to abnormalities in her radiograph. She had no history of facial pain, rhinorrhea, chronic sinusitis, nasal congestion, sinonasal surgery, or trauma. Endoscopic evaluation and CT scan revealed isolated right-sided maxillary sinus and uncinate process aplasia. It is crucial for otolaryngologists, dentists, maxillofacial surgeons, and radiologists to be familiar with the anatomical variations of the paranasal sinuses to prevent potential complications and surgical errors in this area.