Simple bone cysts (SBCs) are benign lesions often found in the long bones of children between their first and second decades. They occasionally occur in the mandible but rarely in the mandibular condyle. A case of a 7-year-old female child with an increasing enlargement of the left mandibular condyle is presented. A 2 cm × 3 cm lytic lesion was explored and curetted through an intraoral vestibular incision and proved to be an SBC. Postoperative recovery was uncomplicated with remodeling of the condylar observed at 3 years follow-up.