A 15-year-old was arrested in Baldivis overnight after a disturbance outside a party.
Just after 11pm, police received reports of a brawl involving more than 20 people on Rubens Court.
When police arrived, bottles and rocks were being thrown at houses before the group turned on police and started throwing rocks at them.
The 15-year-old was arrested for obstructing police and disorderly behaviour, while 15 other juveniles were detained by police under the S41 Child and Community Services Act and taken to Rockingham Police Station where they were collected by responsible adults.
Two liquor infringement notices were issued as well as one juvenile caution.