Orbital cellulitis, also known as post septal cellulitis, is a bacterial infection of structures within the orbit. It is often caused by spread from sinusitis, periorbital skin infection, or bacteremia, but may occur as the result of direct inoculation from trauma, foreign body, or recent eye surgery. Patients may present with periorbital swelling, proptosis, chemosis, painful extraocular movements, eye pain, fever, or changes in visual acuity. The infection is commonly polymicrobial in nature involving staphylococcal species, streptococcal species, moraxella catarrhalis, and anaerobes. Serious complications can include meningitis, brain abscess, cavernous sinus thrombosis, and blindness. Definitive diagnosis is made through computed tomography and should be followed by immediate ophthalmologic consultation and admission for parental antibiotics.