Police officials said a 29-year-old woman was the only passenger on a bus as she was travelling to her village in northern Punjab state on Friday night.
They said the driver did not stop at her village despite her repeated pleas and drove her to a desolate location, where he and the conductor took her to a nearby building.
They were joined by five friends, and they took turns raping her throughout the night, dropping her off at her village early on Saturday, police said.
The extent of her injuries are not known.
The six suspects arrested on Saturday appeared in a local court Sunday, according to police officer Gurmej Singh.
“The judge has granted three days of police remand. They will be produced in the court again after that,” Singh said, adding that the medical examination of the rape victim had taken place.