Denisova Cave (Russian: Денисова пещера, romanized: Denísova peshchéra, lit. 'the cave of Denis') is a cave in the Bashelaksky Range of the Altai Mountains in Siberia, Russia.

It is widely known for having provided items of great paleoarchaeological and paleontological interest. In particular, the 2008 discovery of bone fragments that in 2010 have been conclusively established to have belonged to a separate early human species - the Denisova hominin - which is named after the cave. Other items including artifacts dated to around 40,000 BP. Remains of a 32,000-year-old prehistoric species of horse have also been found in the cave.

The cave is located in a region thought to have been inhabited concurrently in the past by Neanderthals and by modern humans. A bone needle dated to 50,000 years ago was discovered at the archaeological site in 2016 and has been described as the most ancient needle known (though another possible needle dates to about 10,000 years earlier from South Africa from c. 61,000 years ago).

Denisovans, Neanderthals and related hybrids may have inhabited the Denisova Cave for extended periods, but perhaps not at the same time. The attribution of the needle and certain other artifacts at the cave, whether to Homo sapiens or to the Denisova hominin is uncertain.

The "mystery population" of Homo colloquially referred to as "Denisovans" was for a time also sometimes referred to by the scientific name Homo denisova after the cave, until June 2025, when Denisovans were confirmed to be Homo longi, making H. denisova a junior synonym.

Located in Altai Krai, near the border with Altai Republic, both in Russia, the cave is near the village of Chorny Anui (Чёрный Ануй), and some 150 km (93 mi) south of Barnaul, the regional capital. The cave, which is approximately 28 m (92 ft) above the right bank of the Anuy River (a left tributary of the Ob), has formed in upper Silurian limestone and contains a floor area of about 270 m² (2,900 sq ft). The cave is composed of three galleries. The central chamber, the Main Gallery, contains a floor of 9 m × 11 m (30 ft × 36 ft) with side galleries, the East Gallery and the South Gallery. It has been described both as a karst cave and as a sandstone cave.

Cave sediments are rich with remnants of animals, including extinct ones. Remains of 27 species of large and medium-sized mammals have been found, (such as cave hyena, cave lion, etc.) and 39 species of small mammals, as well as remnants of reptiles, 50 bird species and other vertebrates. Pollen in the cave sediments is used for palaeoclimatological research.

In the 18th century, the cave was inhabited by an Old Believer hermit, Dyonisiy (Denis), and was named after him.