It happened at Chicago Public Schools' Corliss High School on East 103rd Street in the city's Pullman neighborhood.
The school's principal said pepper spray was used during the fight. How the fight started was not immediately clear.
The principal said school staff deescalated the situation, and all students and staff are safe.
The Chicago Fire Department transported multiple people from the scene to hospitals, and everyone is expected to be OK.
Further information was not immediately available.
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