One woman was seriously injured and underwent surgery during the night. Her condition is not considered life-threatening, according to Örebro police.
In the car with the woman were her 13-year-old daughter and a further four people in their twenties. The other car was carrying only the driver.
"As I understand it it is the car with many people which has crashed into the one with the single person," Henrik Dahlström at Örebro police told the Expressen daily.
Emergency services arrived at the scene shortly after and spent 35-40 minutes there ensuring that all the injured had been taken care of.
The collision occurred at around 2am on highway 50 in Lillån in the northern part of Örebro. One of the drivers is suspected of running a red light at road junction.
There were significant amounts of debris left at the scene and a lamp post is reported to have been knocked over in the crash.
"It was pretty chaotic at the scene at first," according to an Örebro police officer.
Police had not opened any investigation into a suspected offence on Saturday morning, focusing instead on seeing to it that the injured received care.
Follow The Local on Twitter