The incident occurred at about 12:36 a.m. on a train in the 700-block of South Cicero Avenue.
Police said multiple male suspects got into a verbal argument with the 21-year-old victim.
The argument then escalated and the woman was stabbed multiple times with a sharp object, police said.
The victim got off the train at a stop in Oak Park and she was transported to Loyola Hospital, where she was listed in fair condition.
No one is in custody and Area Four detectives are investigating.
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