The Tatra Mountains (pronounced^ⓘ), Tatras (Tatry either in Slovak (pronounced [ˈtatri] ^ⓘ) or in Polish (pronounced [ˈtatrɨ]) - plurale tantum), are a series of mountains within the Western Carpathians that form a natural border between Slovakia and Poland. They are the highest mountains in the Carpathians. The Tatras are distinct from the Low Tatras (Slovak: Nízke Tatry), a separate Slovak mountain range further south.

The Tatra Mountains occupy an area of 785 square kilometres (303 sq mi), of which about 610 square kilometres (236 sq mi) (77.7%) lie within Slovakia and about 175 square kilometres (68 sq mi) (22.3%) within Poland. The highest peak, called Gerlachovský štít, at 2,655 metres (8,711 feet), is located north of Poprad, entirely in Slovakia. The highest point in Poland, Rysy, at 2,500 metres (8,200 ft), is located southeast of Zakopane, on the border with Slovakia.

The Tatras' length, measured from the eastern foothills of the Kobylí vrch (1,109 metres (3,638 ft)) to the southwestern foot of Ostrý vrch (1128 m), in a straight line, is 57 km (35 mi) (or 53 km (33 mi) according to some), and strictly along the main ridge, 80 km (50 mi). The range is only 19 km (12 mi) wide. The main ridge of the Tatras runs from the village of Huty at the western end to the village of Ždiar at the eastern end.

The Tatras are now protected by law by the establishment of the Tatra National Park, Slovakia and the Tatra National Park, Poland, which are jointly entered in UNESCO's World Network of Biosphere Reserves. In 1992, UNESCO jointly designated the Polish and Slovak parks a transboundary biosphere reserve in the World Network of Biosphere Reserves, under its Man and the Biosphere Programme.

The first written record of the name is from 999, when the Bohemian Duke Boleslaus II, on his deathbed, recalled when the Duchy of Bohemia extended to the Tritri montes. Another mention is in the 1086 document from Henry IV, wherein he referred to the Diocese of Prague with Tritri mountains. Still another is in 1125, where the Kosmas chronicles (Chronica Boemorum) mention the name Tatri.

In 1790 Belsazar Hacquet wrote that Slavs call these mountains Tatari or Tatri because there used to be Tatar hordes roaming the area.

Machek in 1931 favored the theory of the Polish linguist Rozwadowski with a syllabic r like in the words chrt (Czech hound), smrt (Czech death). In Czech this syllabic is sometimes with vowels i, e or u for example črný – černý, so the Czech reconstruction from Tritri/Tritry would be Trtry. In Polish, the term Tatry is firstly mentioned in 1255. Syllabic r often has vowels on both sides in Polish, so in the case of Tarty, we can reconstruct the name to Tartry, where the vowel a originated before the syllabic r, which dissimilated. This theory is supported by Hungarian forms Turtur, Turtul, and Tortol from the 12th to 14th centuries. It is unclear what form the Slovak term took before the 17th century when the first references to Tatry appear, probably as a loan word from Polish that later found its way into Czech and Hungarian. The term Tatra also appears as a general term in Slovak for barren or stony land, and also in Ukraine for small stones in a river. Machek stresses that the name has no Slavic origin and mentions Rozwadowski's theory of an Illyrian origin because of a connection with a Herzegovian highland called Tatra, thus taken from local inhabitants. The name is also close to the Ukrainian word for gravel, toltry.

The Tatras are a mountain range of a corrugated nature, originating from the Alpine orogeny, and therefore characterized by a relatively young-looking lie of the land, quite similar to the landscape of the Alps, although significantly smaller. It is the highest mountain range within the Carpathians.