Background: The outbreak of coronavirus disease 2019 (COVID-19) is evolving rapidly. However, there is limited information about this disease in children and adolescents. Only a few pediatric cases of COVID-19 have been reported so far. Since the immune responses of children are different from adults, their clinical findings and therapeutic responses may differ. To the best of our knowledge, this is the first confirmed case of COVID-19 in a 12-year-old girl with abdominal pain in Iran. Case Presentation: A 12-year-old girl with a history of cold, dry cough, sore throat, fever, and left-sided abdominal pain was referred to the Children’s Medical Center, Tehran, Iran, on March 7, 2020. The chest X-ray indicated air space opacification in the right lower lobe and faint ground-glass opacity in the left lower lung. A subsequent chest computed tomography (CT) scan indicated blialteral patchy lower lobe consolidations. The patient’s oropharyngeal swab was positive for COVID-19, based on the result of real-time reverse transcription-polymerase chain reaction (rRT-PCR) assay. The patient’s clinical status was improved, and she was discharged five days after admission (March 11, 2020). Conclusion: Since the number of infected cases with COVID-19 is growing rapidly in Iran, early detection and management of infected cases are highly recommended for preventing the disease transmission and reducing the rate of infection.