ThinkPad is a line of business-oriented laptop and tablet computers produced since 1992. It was originally designed, created and manufactured by the American International Business Machines (IBM) Corporation. IBM sold its PC business to the Chinese company Lenovo in 2005 and since 2007 all ThinkPad models have been manufactured by them.

The ThinkPad line was first developed at the IBM Yamato Facility in Japan; they have a distinct black, boxy design, which originated in 1990 and is still used in some models. Most models also feature a red-colored trackpoint on the keyboard, which has become an iconic and distinctive design characteristic associated with the ThinkPad line. It has seen significant success in the business market while certain models target students and the education market. ThinkPad laptops have been used in outer space and for many years were the only laptops certified for use on the International Space Station (ISS). ThinkPads have also for several years been one of the preferred laptops used by the United Nations.

Following the failure of its first laptop computer, the PC Convertible, IBM was the last of the major personal computer manufacturers to enter the fast-growing notebook market, launching the PS/2 Note in 1992. Building on the PS/2 Note, the ThinkPad was developed to compete with Compaq in the United States, whose LTE was the first commercially successful notebook PC; as well as Apple Computer's highly successful PowerBook, and Toshiba in Japan, whose Dynabook series of notebooks were similarly successful. IBM signed a lucrative contract with the Harvard Business School to provide the campus with notebook PCs. The task of creating a notebook was given to the Yamato Facility in Japan, headed by Arimasa Naitoh (内藤在正, Naitō Arimasa; Vice President of Lenovo's PC and Smart Devices business unit), a Japanese engineer and product designer who had joined IBM in the 1970s, now known as the "Father of ThinkPad".

The name "ThinkPad" was a product of IBM's corporate history and culture. Thomas J. Watson Sr. first introduced "Think" as an IBM slogan in the 1920s. With every minicomputer and mainframe IBM installed (almost all were leased – not sold), a plastic sign with the text "Think" printed on an aluminum plate was placed atop the operator's console.

For decades, IBM had also distributed small notepads with the word "THINK" emblazoned on their cover to customers and employees. The name "ThinkPad" was suggested by IBM employee Denny Wainwright, who had one such notepad in his pocket. The name was opposed by the IBM corporate naming committee as all the names for IBM computers were numeric at that time, but "ThinkPad" was kept due to praise from journalists and the public.

In April 1992, IBM announced the first ThinkPad models, the 300, 700, and 700C all released on October 5, 1992. The 700T released in 1993 was a tablet computer.

This machine was the first product produced under IBM's new "differentiated product personality" strategy, a collaboration between Richard Sapper and Tom Hardy, head of the corporate IBM Design Program. Development of the 700C also involved a close working relationship between Sapper and Kazuhiko Yamazaki, lead notebook designer at IBM's Yamato Design Center in Japan and liaison between Sapper and Yamato engineering.

This 1990–1992 "pre-Internet" collaboration between Italy and Japan was facilitated by a special Sony digital communications system that transmitted high-res images over telephone lines. This system was established in several key global Design Centers by Hardy so IBM designers could visually communicate more effectively and interact directly with Sapper for advice on their projects. For his innovative design management leadership during ThinkPad development, Hardy was named "Innovator of the Year 1992" by PC Magazine.