Two Grade 12 pupils at Johannesburg's Parktown Boys' High were suspended on Friday after an altercation which went viral in a video.
In the video widely circulated on social media, one boy is seen accosting and violently attacking another outside the school tuck shop.
Other pupils are seen intervening and stopping the fight.
According to the Gauteng Department of Education, the fight took place on Thursday.
MEC Panyaza Lesufi condemned the incident, denouncing the "ill-discipline" shown by the two pupils.
"We do not tolerate any sort of violent behaviour in our schools. Learners must focus on their studies and if a matter arises which bothers them; they must consult with their educators or principals about it - instead of taking matters into their own hands," said Lesufi.
Department spokesperson Steve Mabona said a disciplinary hearing would be held soon.