There were also incidents in other parts of Värmland in connection with the European Rallycross Championships in Höljes.
Police do not want to reveal how many were involved in the gang rape.
“Two have been arrested for gang rape. That is all we want to say,” Morgan Connedal of the Värmland police told TT news agency.
The suspects were arrested on Sunday afternoon.
Another rape was reported on Saturday night, but no suspect has been arrested. A total of four rapes were reported during the festival.
Värmland police have had their hands full over the weekend. Besides the rapes, 13 people were arrested for drunkenness and 12 for various narcotics-related offenses at the music festival on Saturday night.
In addition, a man was seriously burned on a spirit stove at a camping site. He was taken to Uppsala University hospital with burn injuries.
Police also confiscated around 800 litres of alcohol during the week of the festival.
“We have been very thorough about not letting minors bring alcohol into the area, so we confiscated quite a bit already at the beginning,” said Per Ström, information officer at the Värmland police.
There were also several alcohol-related incidents and fights in connection with the European Rallycross Championships in Höljes. Eleven people were taken into custody for drunkenness and several more for assault.