The Moray Firth (Scottish Gaelic: An Cuan Moireach or Linne Mhoireibh) is a roughly triangular inlet (or firth) of the North Sea, north and east of Inverness, which is in the Highland council area of Scotland. It is the largest firth in Scotland, stretching from Duncansby Head (near John o' Groats) in the north, in the Highland council area, and Fraserburgh in the east, in the Aberdeenshire council area, to Inverness and the Beauly Firth in the west. Therefore three council areas have Moray Firth coastline: Highland to the west and south of the Moray Firth and Highland, Moray and Aberdeenshire to the south. The firth has more than 800 kilometres (about 500 miles) of coastline, much of which is cliff.

A number of rivers flow into the Moray Firth, including the River Ness and the River Spey. Various smaller firths and bays are inlets of the firth, including the Cromarty Firth and the Dornoch Firth. The Pentland Firth has its eastern mouth at the Moray Firth's northern boundary.

The Moray Firth is effectively two firths, the Inner Moray Firth, which was traditionally known as the Firth of Inverness, and the Outer Moray Firth which is more open North Sea water. The name "Firth of Inverness" is rarely found on modern maps, but extended from the Beauly Firth in the west, to Chanonry Point in the east.