At about 1:30 p.m., the man was found with a stab wound to the chest in the 4900-block of Oak Street, Hammond police said. The man later died at a hospital.
The 17-year-old suspect was located shortly afterward in the 4900-block of Columbia Avenue in Hammond.
A motive was not immediately known, police said.
Anyone with information is asked to call Hammond detectives at 219-852-2906.