The Sacred Valley of the Incas (Spanish: Valle Sagrado de los Incas; Quechua: Willka Qhichwa), or the Urubamba Valley, is a valley in the Andes of Peru, north of the Inca capital of Cusco. It is located in the present-day Peruvian region of Cusco. In colonial documents it was referred to as the "Valley of Yucay". The Sacred Valley was incorporated slowly into the incipient Inca Empire during the period from 1000 to 1400.

The Sacred Valley is a major tourist destination. In 2019, 1.6 million people, the majority non-Peruvians, visited Machu Picchu, its most famous archaeological site. Many of the same tourists also visited other archaeological sites and modern towns in the Sacred Valley.

Stretching from Pisac to Ollantaytambo, this fertile valley is irrigated by the Urubamba River. The Chanapata civilisation first utilised this area starting at around 800 BCE because of its rich soil used for agriculture. The Qotacalla civilization lived in the Sacred Valley from 500 to 900 CE. The Killke civilization then flourished in the Sacred Valley from 900 until it was absorbed into the Incan Empire in 1420. The Incan Empire ruled this area for little more than 100 years until the arrival of the Spanish.

The valley, running generally west to east, is understood to include everything along the Urubamba River between the town and Inca ruins at Písac and Machu Picchu, 100 kilometres (62 mi) distant. The Sacred Valley has elevations above sea level along the river ranging from 3,000 metres (9,800 ft) at Pisac to 2,050 metres (6,730 ft) at the Urubamba River below the citadel of Machu Picchu. On both sides of the river, the mountains rise to much higher elevations, especially to the north where two prominent mountains overlook the valley: Sahuasiray, 5,818 metres (19,088 ft) and Veronica, 5,893 metres (19,334 ft) in elevation. The intensely cultivated valley floor is about 1 kilometre (0.62 mi) wide on average. Side valleys and agricultural terraces (andenes) expand the cultivatable area.

The valley was formed by the Urubamba river, also known as the Vilcanota River, Willkanuta River (Aymara, "house of the sun") or Willkamayu (Quechua). The latter, in Quechua, the still spoken lingua franca of the Inca Empire, means the sacred river. It is fed by numerous tributaries which descend through adjoining valleys and gorges and contains numerous archaeological remains and villages. The Sacred Valley was the most important area for maize production in the heartland of the Inca Empire and access through the valley to tropical areas facilitated the import of products such as coca leaf and chile peppers to Cuzco.

The climate of Urubamba is typical of the valley. Precipitation, concentrated in October through April, totals 527 millimetres (20.7 in) annually and monthly average temperatures range between 15.4 °C (59.7 °F) in November, the warmest month, to 12.2 °C (54.0 °F) in July, the coldest month. The Incas built extensive irrigation works throughout the valley to counter deficiencies and seasonality in precipitation.

The early Incas lived in the Cusco area. By conquest or diplomacy, during the period 1000 to 1400 CE, the Inca achieved administrative control over the various ethnic groups living in or near the Sacred Valley.

The attraction of the Sacred Valley to the Inca, in addition to its proximity to Cusco, was probably that it was lower in elevation and therefore warmer than any other nearby area. The lower elevation permitted maize to be grown in the Sacred Valley. Maize was a prestige crop for the Incas, especially to make chicha, a fermented maize drink the Incas and their subjects consumed in large quantities at their many ceremonial feasts and religious festivals.