South Asia or Southern Asia is a term used to represent the southern region of the Asian continent, which comprises the sub-Himalayan SAARC countries and, for some authorities, adjoining countries to the west and east. Topographically, it is dominated by the Indian Plate, which rises above sea level as Nepal and northern parts of India situated south of the Himalayas and the Hindu Kush. South Asia is bounded on the south by the Indian Ocean and on land (clockwise, from west) by West Asia, Central Asia, East Asia, and Southeast Asia. The terms "Indian subcontinent" and "South Asia" are sometimes used interchangeably.

The current territories of Afghanistan, Bangladesh, Bhutan, Maldives, Nepal, India, Pakistan, and Sri Lanka form the countries of South Asia. In addition, with deviating definitions based on often substantially different reasons, the British Indian Ocean Territory, Mauritius, and the Tibet Autonomous Region are included as well. South Asia is home to well over one fifth of the world's population, making it both the most populous and the most densely populated geographical region in the world. The South Asian Association for Regional Cooperation(SAARC) is an economic cooperation organisation in the region which was established in 1985 and includes all eight nations comprising South Asia.