A ceiling has collapsed on pupils at Kgomba Primary School in Hammanskraal, the Gauteng Department of Basic Education said.
According to spokesperson Steve Mabona, the ceiling collapsed on Thursday while the pupils were in class, adding paramedics had rushed to the school shortly after the incident.
Education MEC Panyaza Lesufi and his team had also gone to the school to assess the situation.
The Pretoria North Rekord quoted Mabona as saying 20 Grade 6 pupils were injured and taken to a nearby clinic.
“None of the learners were admitted to hospital.”
Mabona said the ceiling was held in place by nails when it collapsed.
In another incident, 17 pupils at Lofentse Girls School in Soweto were hospitalised after allegedly consuming cakes laced with marijuana, commonly known as space cakes, on Thursday.
They were rushed to Baragwanath and Lillian Ngoyi hospitals. A psychosocial team will be sent to the school on Friday to provide support and counselling.
Mabona said an investigation into the incident had been launched.