Orbital cellulitis is an infectious disease that usually occurs in children between 5 and 12 years old. The most frequently involved microorganisms in 95% of cases are Staphylococcus Aureus, Streptococcus Pneumoniae, Haemophilus Influenzae and Moraxella Catarrhalis. The cases of orbital cellulitis occur with a frequency of 6 to 27%, and the incidence of orbital abscesses as a complication of sinusitis is between 1 to 2%. The aim of this case is to report a case of orbital cellulitis complicated by subperiostal abscess caused by Streptococcus Mitis, which is rare in pediatric population. To report a case of periorbital cellulitis progressing to subperiosteal abscess caused by Streptococcus Mitis that was isolated in our laboratory in a two years old, previously healthy boy, with a 3 days history of progressively worsening swelling of the left eye. He was diagnosed with periorbital cellulitis progressing to subperiostal abscess caused by Streptococcus Mitis. Early surgical intervention with aggressive medical management was needed. to our knowledge this is the first case of periorbital cellulitis associated with Streptococcus Mitis organism in the pediatric age group.