Paediatric orbital cellulitis is a potential sight- and life-threatening condition. It is a serious infection in children that can result in significant complications, including blindness, cavernous sinus thrombosis, cerebral venous sinus thrombosis, meningitis, subdural empyema, and brain abscess. Of the patients with orbital cellulitis, 17% died from meningitis, and 20% of the survivors had permanent loss of vision. Therefore, the potential for sight- and life-threatening complications makes prompt diagnosis and early treatment very important. We report here a case of a two-year-old girl who presented with a three-day history of left periorbital swelling, preceded by left upper perioral swelling that extended upward to the left cheek and left lower lid and was associated with low-grade fever. The patient had been admitted and was treated as having left preseptal with facial cellulitis; the patient was started on intravenous amoxicillin/clavulanic acid (200 mg three times per day dose), and chloramphenicol ointment was applied to the periorbital area. On day 3, the condition worsened, and dental examination showed multiple dental caries, upper gum swelling and abscess, and mobility of teeth 61 and 62 (two baby teeth). Contrast-enhanced computed tomography (CECT) of the orbit, paranasal, and brain showed a left periosteal abscess collection extending to the inferomedial region of the orbit. Examination and tooth extraction were performed under general anesthesia. The intraoperative results showed the presence of a left upper gum abscess, which was possibly the primary source of infection. Clinical improvement was observed postoperatively. Orbital cellulitis can be a complication of a dental abscess. This case emphasizes the importance of primary tooth care in children. A lack of care can result in fatal complications.