A recent global outbreak of cases of acute hepatitis of unknown origin in children has raised health alerts. Increasing numbers of cases are being reported in most countries, mainly in the United Kingdom (UK). Although the cause remains unknown, several viruses have been isolated from affected children, including adenovirus, severe acute respiratory syndrome coronavirus 2 (SARSCoV2), Epstein-Barr virus (EBV), and rhinovirus. Notably, the cause is not from common hepatitis viruses, as serology for hepatitis viruses A, B, C, D, and E has been negative. Current causal hypotheses include possible infection with a new adenovirus variant that affects immunocompetent children, a new pediatric manifestation of COVID-19, or coinfection with enteric adenovirus type F41. This Editorial aims to present current hypotheses regarding the etiology of acute hepatitis of unknown origin in children, including the role of autoimmune hepatitis secondary to viral infection.