Loch Fyne is a sea loch on the west coast of Argyll and Bute, Scotland. It extends 65 kilometers (40 miles) inland from the Sound of Bute , making it the longest of the sea lochs. It is connected to the Sound of Jura by the Crinan Canal.

Loch Fyne is a popular area for sport diving and fishing. It is also a popular tourist destination with attractions such as Inveraray Castle and the ruined Castle Lachlan nearby.

Dolphins and seals inhabit the loch, and basking sharks can be found in its waters during the summer months.

Over half a million troops were trained in amphibious landing techniques on the shores of Loch Fyne prior to the D-day landings.

Loch Fyne at Inverary harbour