Police said the shooting happened in the Logan Square neighborhood's 1700-block of North Harding Avenue around 12:15 a.m.
A 25-year-old woman was outside when someone shot her in the shoulder, police said.
The victim was taken to Stroger Hospital in critical condition.
Summer 2025 violence: Tracking shootings across Chicago Live updates
There is no one in custody, and Area Five detectives are investigating.
Police did not immediately provide further information about the shooting.
INTERACTIVE SAFETY TRACKER Track crime and safety in your neighborhood