Police Scotland said the girl was crossing Main Street, near Belhaven Terrace, at about 17:35 on Friday when she was struck by the bus.
She was taken to Wishaw General Hospital and her condition was described as serious.
The driver of the bus and the passengers aboard were uninjured. The road was closed for about four hours.
An eight-year-old girl has been seriously injured when she was hit by a bus in Wishaw in North Lanarkshire.