Rannoch Moor (Scottish Gaelic: Mòinteach Raineach/Raithneach) is a large expanse of around 50 square miles (130 km²) of boggy moorland to the west of Loch Rannoch, in Perth and Kinross and Lochaber, Highland, partly northern Argyll and Bute, Scotland. Rannoch Moor is designated a Site of Special Scientific Interest (SSSI) and a Special Area of Conservation.

It is notable for its wildlife, particularly famous for the sole British location for the Rannoch-rush, named after the moor. It was also frequently visited by Horace Donisthorpe, who collected many unusual species of ants on the moor and surrounding hilly ground. Today it is still one of the few remaining habitats for Formica exsecta, the "narrow-headed ant", although recent surveys have failed to produce any sign of Formica pratensis, which Donisthorpe recorded in the area in the early part of the 20th century.

Peat deposits pose major difficulties to builders of roads and railways. When the West Highland Line was built across Rannoch Moor, its builders had to float the tracks on a mattress of tree roots, brushwood and thousands of tons of earth and ashes.