Trotternish (Scottish Gaelic: Tròndairnis) is the northernmost peninsula of the Isle of Skye in Scotland, spanning in length from Portree to Rubha Hunish. The Trotternish escarpment runs almost the full length of the peninsula, some 30 kilometres (20 miles), and contains landmarks such as the Old Man of Storr and the Quiraing. The summit of The Storr, overlooking the Old Man, is the highest point of the peninsula at 719 m above sea level. The north-eastern part of the peninsula around Quiraing is designated as a National Scenic Area and the entire escarpment is a Special Area of Conservation.

Dinosaur footprints have been found at An Corran, which is also a Mesolithic hunter-gatherer site dating to the 7th millennium BC. The ruins of the 14th–15th-century Duntulm Castle stand at the northern end of the peninsula.

The three major settlements on Trotternish are Portree, generally regarded as the capital of Skye, Uig, a ferry terminus, and the township of Staffin. Trotternish is the strongest Gaelic-speaking area of Skye.

Trotternish is underlain by basalt, which provides relatively rich soils and a variety of unusual rock features. The Kilt Rock is named after the tartan-like patterns in the 105-metre (344-foot) cliffs. The Quiraing is a spectacular series of rock pinnacles on the eastern side of the main spine of the peninsula and further south is the rock pillar of the Old Man of Storr.

Trotternish is also known for its Middle Jurassic aged rocks (c. 174–164 million years old), which yield a variety of fossils including dinosaurs. These are strictly protected by law by the Skye Nature Conservation Order 2019. Dinosaurs known from Trotternish include theropods, sauropods, thyreophorans, and possible ornithopods. Many of Skye's dinosaur body fossils and footprints can be viewed at the Staffin Museum in Ellishadder, Staffin. The most accessible shoreline localities to view dinosaur footprints include Duntulm, Brother's Point, and An Corran.

The north-eastern part of the peninsula around Quiraing is designated as the Trotternish National Scenic Area, one of the forty such areas in Scotland, which are defined so as to identify areas of exceptional scenery and to ensure its protection from inappropriate development. The designated area covers 7,919 ha in total, of which 6,128 ha is on land, with a further 1789 ha being marine (i.e. below low tide level, and covering the seas to the east of the peninsula).

The entire length of the Trotternish escarpment is protected as a Special Area of Conservation under the Natura 2000 programme, and classified as a Category IV protected area by the International Union for Conservation of Nature.

A Mesolithic hunter-gatherer site dating to the 7th millennium BC at An Corran in Staffin is one of the oldest archaeological sites in Scotland. The site continued to be used over many millennia with human bones radiocarbon-dated to the Neolithic (dated to around 3500 BC) and Bronze Age (dated to between 2560 and 2150 BC) periods and a copper-alloy pin from the Late Bronze Age/Early Iron Age being found, as well as more modern 19th-20th century materials.