Etopic tooth eruption is the occurrence of the tooth germ in a nonanatomical position. It can be associated with dentigerous cyst, which is the second most seen in the development of odontogenic cyst commonly presented in mandibular region and seen in single form. It is usually accompanied with mandibular third molar followed by canine. Bilateral and multiple dentigerous cysts in nonsyndromic patients are fairly rare phenomenon and barely documented in the literatüre. We report a rare case of bilateral dentigerous cysts associated with ectopic third molars in the maxillary sinuses. Computerized tomography scan confirmed the diagnosis. A 32-year-old female patient manifesting as postnasal discharge accompanied with chief complaint of nasal obstruction, pain at blinking right eye from pressure of cyst at the inferior orbital rim, and headache for the last 1 year. This report presented our management of rarely seen case of bilateral dentigerous cysts related with ectopic third molars in maxillary sinuses. Ectopic teeth eruption in maxillary sinus should be treated as early as possible once it is diagnosed, in consideration of related complication of orbital and nasal involvement. The symptoms totally recovered with the suitable management method for our patient. The prevalence of maxillary third molars ectopic eruption in the maxillary sinus (Antrum of Highmore) is extremely rare in the literature. Lack of treatment protocol for such ectopic eruptions in the maxillary sinus and its rareness deserved to be added to the literature.