The Matterhorn 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) above sea level, making it one of the highest summits in the Alps and Europe. Sometimes referred to as the "Mountain of Mountains" (German: Berg der Berge), it has become an indelible emblem of the Alps and stands as the most photographed mountain in the world. The Matterhorn has four faces, each roughly oriented toward one of the four cardinal points. Three of these (north, east, and west) are on the Swiss side of the border and watershed, while the south face lies on the Italian side. These four steep faces, rising above the surrounding glaciers, are separated by the Hörnli, Furggen, Zmutt, and Leone (Lion) 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 18th century; this 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. 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.

The name Matterhorn derives from the German words Matte ("meadow") and Horn ("horn"), and is often translated as "the peak of the meadows".

In the Schalbetter map, printed by Sebastian Münster in 1545, the valley is labelled Mattertal, but the mountain has the Latin name Mons Silvius as well as the German name Augstalberg, in concord with the Aosta Valley (German Augstal). The 1548 map by Johannes Stumpf gives only Mons Silvius.

The French name Cervin, from which the Italian term Cervino derives, stems from the Latin Mons Silvanus (or Mons Sylvanus), where silva means "forest"; this was corrupted to Selvin and then Servin. The change of the first letter "s" to "c" is attributed to Horace Bénédict de Saussure, who thought the word was related to "deer" (French: cerf and Italian: cervo).

Josias Simler hypothesized in De Alpibus Commentarius (1574) that the name Mons Silvius derived from a Roman leader, a hypothesis that was readopted by T. G. Farinetti: "Silvius was probably a Roman leader who sojourned with his legions in the land of the Salassi and the Seduni, and perhaps crossed the Theodul Pass between these two places. This Silvius may have been that same Servius Galba whom Caesar charged with the opening up of the Alpine passes, which from that time onward traders have been wanting to cross with great danger and grave difficulty. Servius Galba, in order to carry out Caesar's orders, came with his legions from Allobroges (Savoy) to Octodurum (Martigny) in the Valais, and pitched his camp there. The passes which he had orders to open from there could be no other than the St. Bernard, the Simplon, the Theodul, and the Moro; it therefore seems likely that the name of Servius, whence Silvius and later Servin, or Cervin, was given in his honour to the famous pyramid." It is unknown when the new name of Servin, or Cervin, replaced the old, from which it seems to be derived.

The Matterhorn is also named Gran Bècca ("big mountain") by the Valdôtains and Horu by the local Walliser German speaking people.