The principal of Hoërskool Roodepoort in Johannesburg was stabbed on the hand while trying to defuse a violent clash between pupils from her school and those from West Ridge High School in Gauteng.
Gauteng Department of Education spokesperson Steve Mabona said pupils from the two schools fought for the first time last Friday.
Footage of that altercation went viral on social media over the weekend.
Pupils from West Ridge High School then allegedly returned to Hoërskool Roodepoort on Monday seeking revenge.
They allegedly attacked pupils and pelted cars with stones.
Three Hoërskool Roodepoort pupils sustained serious injuries and are receiving medical care.
At least six Grade 12 boys from West Ridge High School have been identified as part of the attacking group and will receive suspension letters.
Mabona said affected pupils and teachers would receive psychosocial support and other counselling services.
