The 23-year-old woman shot the man in the arm about 11:50 a.m. in the 2700 block of West 59th Street, Chicago police said.
The man, 30, went to the University of Chicago Medical Center in good condition, police said. The woman was uninjured.
Officers recovered two guns from the apartment where the shooting happened, police said.
No charges have been filed.
On social media, police shared a photo of one of the guns, a 9mm pistol with a 30-round magazine and suppressor.