Police allege that about 3pm (AWST), a group of youths assaulted the 15-year-old on the grounds of Ellenbrook Secondary College, Ellenbrook, before running away.
The victim suffered lacerations to his arm and head and was taken to hospital.
Just after 4pm yesterday, police arrested six teens – two aged 16, one aged 15, two aged 14, and one aged 13.
They have been charged with multiple offences including assault and wounding.
One of the teens was futher charged with carrying a blade.
Three of the teens will appear in children’s court today, and three at a later date.
The investigation continues, and police urge anybody with information or video footage to contact Crime Stoppers online or on 1800 333 000.