Walkman is a Sony brand tradename originally used for portable audio cassette players, and now used to market Sony's portable audio and video players as well as a line of former Sony Ericsson mobile phones. The original Walkman introduced a change in music listening habits by allowing people to carry music with them and listen to music through lightweight headphones.

The device was built in 1978 by audio-division engineer Nobutoshi Kihara for Sony co-chairman Akio Morita, who wanted to be able to listen to operas during his frequent trans-Pacific plane trips. The original Walkman was marketed in 1979 as the Walkman in Japan, the Soundabout in many other countries including the US, Freestyle in Sweden and the Stowaway in the UK. Advertising, despite all the foreign languages, still attracted thousands of buyers in the US specifically. Morita hated the name "Walkman" and asked that it be changed, but relented after being told by junior executives that a promotion campaign had already begun using the brand name and that it would be too expensive to change.

The names "Walkman", "Pressman", "Watchman", "Scoopman", "Discman", and "Talkman" are trademarks of Sony, and have been applied to a wide range of portable entertainment devices manufactured by the company. The name "Walkman" was based on its precursor, the Pressman tape recorder. An initial prototype of the Walkman was in fact made by replacing the recording circuit and speaker from the Pressman with a stereo amplifier. Sony continues to use the "Walkman" brand name for most of their portable audio devices, after the "Discman" name for CD players was dropped in the late 1990s. According to Sony, the plural form is "Walkman Personal Stereos", rather than "Walkmans" or "Walkmen".