ThinkPad is a line of laptop computers designed, developed and sold by IBM but now produced by Lenovo. They are known for their boxy black design, which was modeled after a traditional Japanese lunchbox. Lenovo purchased IBM's personal computer business and acquired the ThinkPad brand in 2005.

ThinkPads are popular with large businesses and schools. Older model ThinkPads, especially IBM branded models, are revered by technology enthusiasts, collectors and power users due to their design, relatively high resale value, abundance of aftermarket replacement parts and sheer durability. The ThinkPad has also been used in space, and is the only laptop certified for use on the International Space Station.

IBM introduced the ThinkPad line in 1992.

The name "ThinkPad" is a product of IBM's corporate history and culture. Thomas J. Watson, Sr, had first introduced "THINK" as an IBM slogan in the 1920s. For decades IBM distributed small notepads with the word "THINK" emblazoned on a brown leatherette cover to customers and employees. The name ThinkPad was suggested by IBM employee Denny Wainwright, who had a "THINK" notepad in his pocket. The name faced disagreements from the IBM corporate naming committee because the nomenclature system for the IBM computers was then numerical; however, the brand name "ThinkPad" was kept as the press showed appreciation for the title.