The World Is Flat: A Brief History of the Twenty-First Century is an international bestselling book by Thomas Friedman that analyzes globalization, primarily in the early 21st century. The title is a metaphor for viewing the world as a level playing field in terms of commerce, where all competitors have an equal opportunity. As the first edition cover illustration indicates, the title also alludes to the perceptual shift required for countries, companies and individuals to remain competitive in a global market where historical and geographical divisions are becoming increasingly irrelevant.

The book was first released in 2005, was later released as an "updated and expanded" edition in 2006, and yet again released with additional updates in 2007 as "further updated and expanded: Release 3.0." The title was derived from a statement by Nandan Nilekani, the former CEO of Infosys. The World is Flat won the inaugural Financial Times and Goldman Sachs Business Book of the Year Award in 2005.

In his book, The World is Flat, Friedman recounts a journey to Bangalore, India, when he realized globalization has changed core economic concepts.