Loch Fyne, is a sea loch off the Firth of Clyde and forms part of the coast of the Cowal peninsula. Located on the west coast of Argyll and Bute, Scotland. It extends 65 kilometres (40 mi) inland from the Sound of Bute, making it the longest of the sea lochs in Scotland. It is connected to the Sound of Jura by the Crinan Canal. Although there is no evidence that grapes have grown there, the title is probably honorific, indicating that the river, Abhainn Fìne, was a well-respected river.

Loch is a word meaning "lake" or "sea inlet" in Scottish and Irish Gaelic, subsequently borrowed into English. In Irish contexts, it often appears in the anglicized form "lough".