A truck, three minibuses, and five cars rammed into each other 25 kilometres southeast of the Hungarian capital on the M5 motorway, a busy route linking central and southeast Europe.
Eighteen people were seriously injured, and hospital spokespersons said at least six of them were in a critical condition.
The injured included Romanian, Serbian, Bulgarian and Turkish citizens, as well as Hungarians.
Police did not release the nationalities of the fatalities.