Loch Fad is a freshwater loch on the Isle of Bute in Scotland.

Its name means "long loch" in Scottish Gaelic. It lies on the Highland Boundary Fault.

Glacial lake and artificial dam

The ribbon-shaped lake has a length of almost 3 km and a width of 200 to 400 metres. Its deepest point is near the middle of the length.

Adjoining to the north east end of this natural lake, hydrologically