A case of an ameloblastoma of the lacrimal sac is reported. The patient, 46-year-old man, had complained of a swelling on the left inner canthus. Clinical examination showed a pale tumor in the left inferior nasal meatus. A partial maxillectomy was performed. The tumor extended from the lacrimal sac to the inferior nasal meatus through the nasolacrimal duct. Histopathological examination revealed ameloblastoma. Literature on the related subjects is reviewed.