Maxillary sinus odontogenic keratocyst (OKC) is very rare and occupies less than 1% of the total OKC cases reported in the literature. OKCs have characteristic features that are unique compared to other cysts of the maxillofacial region. Considering their peculiar behaviour, varied origin, debated development, discourse treatment modalities, and high recurrence rate, OKCs have been a subject of interest for various oral surgeons and pathologists globally. This case report presents an unusual case of invasive maxillary sinus OKC into the orbital floor, pterygoid plates, and hard palate in a 30-year-old female. The case report confers that cystic maxillary sinus lesions should always be treated very extensively irrespective of the nature of the lesion as the site makes it highly susceptible to secondary infection and recurrence. The case also establishes a set of imaging modalities and specific treatment approaches to be followed for maxillary sinus OKC based on the literature of all the previous cases reported.