The crash occurred at about 9:08 p.m. in the area of Milwaukee Avenue and Winchester Road.
Police said a man driving a Chevrolet Blazer was going northbound through the intersection with a green light when it struck an e-bike going east on Milwaukee Avenue just north of the intersection with Winchester Road.
The e-bike was ridden by two 15-year-old girls, police said.
One girl was transported to Advocate Condell Medical Center and then transferred to Lurie Children's Hospital with life-threatening injuries, police said.
The second girl was transported to Advocate Condell Medical Center with non-life-threatening injuries, police said.
The driver of the Blazer was not injured, police said.