Two adults were seriously injured and needed to be airlifted to hospital after the taxi they were travelling in lost control, veered off the road and crashed into a house off Marinda Road in Boksburg.
ER24 spokesperson, Russel Meiring, said the accident occurred shortly before 08:00 on Saturday.
Meiring said that when ER24 and other emergency services arrived on scene, they found 13 occupants of the taxi had been injured.
"Nine children, aged between 12 and 18, and four adults were found on the scene," he said.
"Paramedics assessed the patients and found that two adults had sustained numerous injuries and were in a critical condition," he said.
Meiring said paramedics had immediately treated the patients and provided the two critically injured with advanced life support interventions.
"Once treated, one of the critically injured was airlifted by the ER24 Oneplan helicopter, while the second was airlifted by another private helicopter, both to Sunshine Hospital," he said.
Meiring said the two other adults and eight children had sustained injuries ranging from minor to moderate. He said the remaining patients were transported by ambulance to the same hospital for further treatment.
He said the local authorities were on the scene to investigate the cause of the collision.