Police said the shooting happened in the Morgan Park neighborhood's 11400-block of South Vincennes Avenue around 11:20 a.m.
Someone accidentally shot a 15-year-old boy in the leg, police said.
The teen went to Roseland Hospital in good condition.
Officers took the alleged shooter into custody, and charges are pending, police said.
Investigators recovered a weapon from the scene.
Area detectives are investigating. Further information was not immediately available.
INTERACTIVE SAFETY TRACKER Track crime and safety in your neighborhood