The Matterhorn (, German: [ˈmatɐˌhɔʁn]; Italian: Cervino, [tʃerˈviːno]; French: Cervin, [sɛʁvɛ̃]; Romansh: Mont(e) Cervin(u)) is a mountain of the Alps, straddling the main watershed and border between Switzerland and Italy. It is a large, near-symmetric pyramidal peak in the extended Monte Rosa area of the Pennine Alps, whose summit is 4,478 metres (14,692 ft) high, making it one of the highest summits in the Alps and Europe. The four steep faces, rising above the surrounding glaciers, face the four compass points and are split by the Hörnli, Furggen, Leone/Lion, and Zmutt ridges. The mountain overlooks the Swiss town of Zermatt, in the canton of Valais, to the northeast; and the Italian town of Breuil-Cervinia in the Aosta Valley to the south. Just east of the Matterhorn is Theodul Pass, the main passage between the two valleys on its north and south sides, which has been a trade route since the Roman Era.

The Matterhorn was studied by Horace-Bénédict de Saussure in the late eighteenth century, and was followed by other renowned naturalists and artists, such as John Ruskin, in the 19th century. It remained unclimbed after most of the other great Alpine peaks had been attained and became the subject of an international competition for the summit. The first ascent of the Matterhorn was in 1865 from Zermatt by a party led by Edward Whymper, but during the descent, a sudden fall claimed the lives of four of the seven climbers. This disaster, later portrayed in several films, marked the end of the golden age of alpinism. The north face was not climbed until 1931 and is among the three biggest north faces of the Alps, known as "The Trilogy". The west face, the highest of the Matterhorn's four faces, was completely climbed only in 1962. It is estimated that over 500 alpinists have died on the Matterhorn, making it one of the deadliest peaks in the world.

The Matterhorn is mainly composed of gneisses (originally fragments of the African Plate before the Alpine orogeny) from the Dent Blanche nappe, lying over ophiolites and sedimentary rocks of the Penninic nappes. The mountain's current shape is the result of cirque erosion due to multiple glaciers diverging from the peak, such as the Matterhorn Glacier at the base of the north face. Sometimes referred to as the Mountain of Mountains (German: Berg der Berge), it has become an indelible emblem of the Alps in general. Since the end of the 19th century, when railways were built in the area, the mountain has attracted increasing numbers of visitors and climbers. Each year, numerous mountaineers try to climb the Matterhorn from the Hörnli Hut via the northeast Hörnli ridge, the most popular route to the summit. Many trekkers also undertake the 10-day-long circuit around the mountain. The Matterhorn has been part of the Swiss Federal Inventory of Natural Monuments since 1983.