The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an Australian territory in the central and central northern regions of Australia. The Northern Territory shares its borders with Western Australia to the west (129th meridian east), South Australia to the south (26th parallel south), and Queensland to the east (138th meridian east). To the north, the territory looks out to the Timor Sea, the Arafura Sea and the Gulf of Carpentaria, including Western New Guinea and other islands of the Indonesian archipelago.

The NT covers 1,349,129 square kilometres (520,902 sq mi), making it the third-largest Australian federal division, and the 11th-largest country subdivision in the world. It is sparsely populated, with a population of only 249,000 as of December 2021 – fewer than half as many people as in Tasmania. The largest population center is the capital city of Darwin.

The archaeological history of the Northern Territory may have begun more than 60,000 years ago when humans first settled this region of the Sahul Continent. From at least the 18th century, Makassan traders began a relationship with the indigenous people of the Northern Territory around the trading of trepang. The coast of the territory was first seen by Europeans in the 17th century. The British were the first Europeans to attempt to settle the coastal regions. After three failed attempts to establish a settlement (1824–1828, 1838–1849, and 1864–1866), success was achieved in 1869 with the establishment of a settlement at Port Darwin.

The economy is based largely on mining and petroleum, which during 2018–2019 contributed 23% of the gross state product, or $5.68 billion, accounting for 92.4% of exports.

The territory's population is concentrated in coastal regions and along the Stuart Highway. Besides the capital of Darwin, the major settlements are (in order of size) Palmerston, Alice Springs, Katherine, Nhulunbuy and Tennant Creek. Residents of the Northern Territory are often known simply as "Territorians" and fully as "Northern Territorians".