ISP troopers responded to the crash in Glenwood on Illinois Route 394, just north of Dyer Road, around 9:50 p.m.
One motorcyclist was heading northbound and rear-ended another motorcycle, causing them both to crash.
The motorcyclist who was rear-ended was pronounced dead on the scene, ISP said. The medical examiner's office later identified her as 24-year-old Sarah Gudeman.
The other motorcyclist was taken to Franciscan Health Munster Emergency Room, where he was pronounced dead. The medical examiner's office later identified him as 22-year-old Justin Fasnacht of Crown Point, Indiana.
ISP said the roadway was closed during the investigation and reopened around 3 a.m. Saturday.
ISP said the investigation is active and did not immediately provide further information.