The double-decker coach, carrying over 50 passengers, was making its way north from Reggio Calabria when it swerved and rolled over on the A1 motorway near the exit for Anagni in Lazio at around 4.30am, La Repubblica reported.
The injured were taken to hospitals in Frosinone and Rome. One woman risks losing an arm, while another risks losing an eye, La Repubblica reported. A male passenger suffered a serious head injury.
The coach was making its way to Milan and Turin. It is not yet known what caused the accident, which led to the north-bound A1 being closed for several hours.