The car drove into the group near Bruneck at around 1 a.m.
The driver survived, but Italian police are now investigating the accident, the Carabinieri State Command said.
According to reports, the victims have yet to be identified.
Not all of the group of tourists knew each other and not all of them had documents with them, the police said.
According to Corriere della Sera newspaper, the driver was a 28-year-old man who "may have had a high level of alcohol in his blood".
"A serious road accident, with 11 injured and 6 people dead occurred last night in Lutago,” the local emergency service tweeted.
The area is located in Italy near the Austrian border and is known as a skiing and winter sports area.
Earlier, three Germans were killed in an avalanche accident in South Tyrol.