Three puipils from Kgoro Ya Thuto High School in Ratanda, Ekurhuleni, were knocked down by a police van during a protest march yesterday.
They were among a group of more than 300 students who were protesting after the government's promise to build them a school had come to nothing.
Police took the injured pupils to Heidelberg Hospital.
Ratanda police spokesman Cyril Khumalo said he had heard about the incident but did not have full details as he was on leave.
Pupils said the Sedibeng East District had promised them a school in 2005, but had not kept its word.
Their protest started on Monday - two days before the start of the new school calendar in the inland provinces.
"We have been accommodated at Khaya Lesedi High School for the past two years. Now we want our own school," said the pupils' leader Zandile Mabaso.
She said they were on a platoon system with pupils from Khaya Lesedi. She claimed they used containers placed inside the school yard as classrooms.
"They (pupils from Khaya Lesedi) come in the morning and our shift starts at 12.30 to 5pm," she said.
Kgoro Ya Thuto had operated from a farm before it was closed in 2005. Pupils said the arrangement was that they would be accommodated at Khaya Lesedi for three months. Thereafter the department would build them their own school.
Gauteng education department spokesman Panyaza Lesufi said the promised school had been built but was not yet ready for occupation.
He said it would not take long before the pupils were placed in the new school.