MV Jupiter was a passenger and vehicle ferry in the fleet of Caledonian MacBrayne in the Firth of Clyde, Scotland. She was the oldest of three "streakers" and the third River Clyde ship to bear the name 'Jupiter'. Her open car deck was accessible by stern and side ramps ro-ro. She entered service in 1974, and operated the Gourock to Dunoon crossing for much of her career. In 2006, she became the oldest vessel in the CalMac fleet and continued in service with them until 2010. Jupiter was sold for breaking in 2011.

Caledonian MacBrayne, in short form CalMac, is the trade name of CalMac Ferries Ltd, the major operator of passenger and vehicle ferries to the west coast of Scotland, serving ports on the mainland and 22 of the major islands. It is a subsidiary of holding company David MacBrayne, which is owned by the Scottish Government.