Burj Khalifa (Arabic: برج خليفة‎ "Khalifa Tower"), known as Burj Dubai prior to its inauguration, is a skyscraper in Dubai, United Arab Emirates, and the tallest man-made structure ever built, at 828 m (2,717 ft). Construction began on 21 September 2004, with the exterior of the structure completed on 1 October 2009. The building officially opened on 4 January 2010, and is part of the new 2 km2 (490-acre) flagship development called Downtown Dubai at the 'First Interchange' along Sheikh Zayed Road, near Dubai's main business district.

The tower's architecture and engineering were performed by Skidmore, Owings, and Merrill of Chicago, with Adrian Smith (now at his own firm) as chief architect, and Bill Baker as chief structural engineer. The primary contractor was Samsung C&T of South Korea. In June 2010, Burj Khalifa was the recipient of the 2010 Best Tall Building Middle East & Africa award by the Council on Tall Buildings and Urban Habitat. On 28 September, 2010 Burj Khalifa won the award for best project of year at the Middle East Architect Awards 2010.

The total cost for the project was about US$1.5 billion; and for the entire "Downtown Dubai" development, US$20 billion. In March 2009, Mohamed Ali Alabbar, chairman of the project's developer, Emaar Properties, said office space pricing at Burj Khalifa reached US$4,000 per sq ft (over US$43,000 per m2) and the Armani Residences, also in Burj Khalifa, sold for US$3,500 per sq ft (over US$37,500 per m2)

Burj Khalifa has been designed to be the centrepiece of a large-scale, mixed-use development that will include 30,000 homes, nine hotels such as The Address Downtown Dubai, 3 hectares (7.4 acres) of parkland, at least 19 residential towers, the Dubai Mall, and the 12-hectare (30-acre) man-made Burj Khalifa Lake.
The building has returned the location of Earth's tallest free-standing structure to the Middle East — where the Great Pyramid of Giza claimed this achievement for almost four millennia before being surpassed in 1311 by Lincoln Cathedral in England.

The decision to build Burj Khalifa is reportedly based on the government's decision to diversify from an oil-based economy to one that is service- and tourism-oriented. According to officials, it is necessary for projects like Burj Khalifa to be built in the city to garner more international recognition, and hence investment. "He (Sheikh Mohammed bin Rashid Al Maktoum) wanted to put Dubai on the map with something really sensational," said Jacqui Josephson, a tourism and VIP delegations executive at Nakheel Properties.