The two victims were sitting on a porch near West Monroe Street and South Pulaski Road in the city's West Garfield Park neighborhood around 10 p.m. That's when police said a person in a passing SUV opened fire.
The boy was shot in both ankles and the woman was shot in the leg. They were both transported to Stroger Hospital, where they were listed in good condition.
Around 2 a.m., police said they had someone in custody in connection with the shooting. Investigators did not release details about that person.
Police said neither victim has a documented gang history. The motive for the shooting is under investigation.