The Lake of Menteith (Scottish Gaelic "Loch Innis MoCholmaig"), or, until the 20th century, the Loch of Menteith, is a loch in Scotland, located on the Flanders Moss, the flood plain of the upper reaches of the rivers Forth and Teith, upstream of Stirling. The only settlement of any size on the Lake of Menteith is Port of Menteith.

The are a number of small islands in the loch. On the largest, Inchmahome, is Inchmahome Priory, an ancient monastery. The priory served as refuge to Mary Queen of Scots in 1547. She was only four years old at the time and stayed for three weeks after the disastrous Battle of Pinkie Cleugh in September of that year.

The Loch is not particularly deep and can freeze over completely in exceptionally cold winters. If the ice becomes thick enough (10 inches (25 cm)) an outdoor curling tournament called The Bonspiel or the Grand Match is held on the loch. The event can attract thousands of curlers despite its rarity. The last Grand Match was held in 1979.

The Lake of Menteith is often thought of as the only body of water in Scotland that is referred to as a lake. Actually, there are others, including four small artificial bodies: Pressmennan Lake, the Lake of the Hirsel, Lake Louise (within the grounds of Skibo Castle) and Cally Lake (near Gatehouse of Fleet). There is also a sea bay near Kirkcudbright known as Manxmans Lake. Nearly all other major bodies of water in Scotland are known as lochs. This unusual name is believed to be a corruption of the Lowland Scots Laich o Menteith, where "laich" simply means "low place".