A woman and a four-year old boy were killed near Bronkhorstspruit when the minibus taxi in which they were travelling rolled on Monday.
Netcare 911 spokesman Chris Botha said a further 14 people were injured, including another four-year-old boy, who was airlifted to hospital.
The other 13 passengers who were injured and whose injuries ranged from minor to serious, were taken by ambulance to various nearby hospitals.
Botha said reports from the scene, about 25 kilometres from Bronkhorstspruit on the R25, indicated that the taxi suffered a blowout as it passed a lorry.
The taxi from Groblersdal rolled several times.