The Tata Nano is a rear-engined, four-passenger city car built by Tata Motors, aimed primarily at the Indian market. The car is very fuel efficient, achieving around 26 kilometres per litre (73 mpg_-imp; 61 mpg_-US) on the highway and around 22 kilometres per litre (62 mpg_-imp; 52 mpg_-US) in the city. It was first presented at the 9th annual Auto Expo on January 10, 2008, at Pragati Maidan in New Delhi, India. Nano had a commercial launch on March 23, 2009 and a booking period from April 9 to April 25, generating more than 200,000 bookings for the car. The sales of the car will begin in July 2009, with a starting price of Rs 115,000, which is approximately equal to UK£1,467 or US$2,421 as of June 2009. This is cheaper than the Maruti 800, its main competitor and next cheapest Indian car priced at Rs 184,641,Tata had sought to produce the least expensive production car in the world— aiming for a starting price of Rs 100,000 (approximately US$2,000 as of June 2009). ^{[update][update]}

In early 2008 the news magazine Newsweek identified the Nano as a part of a "new breed of 21st-century cars" that embody "a contrarian philosophy of smaller, lighter, cheaper" and portend a new era in inexpensive personal transportation — and potentially, "global gridlock".The Wall Street Journal confirmed a global trend toward small cars, which includes the Nano.

"Nano" means "small" in Gujarati, the language of the founders of the Tata Group. "Nano" from the SI prefix for one-billionth is often used to mean "small" in colloquial English.