The Macintosh Plus computer is the third model in the Macintosh line, introduced on January 16, 1986, two years after the original Macintosh and a little more than a year after the Macintosh 512K, with a price tag of US$2,599. As an evolutionary improvement over the 512K, it shipped with 1 MB of RAM standard, expandable to 4 MB, and an external SCSI peripheral bus, among smaller improvements. Originally, the computer's case was the same beige color as the original Macintosh, Pantone 453; however, in 1987, the case color was changed to the long-lived, warm gray "Platinum" color. It is the earliest Macintosh model able to run System Software 5, System 6, and System 7, up to System 7.5.5, but not System 7.5.2.

The Macintosh, later rebranded as the Macintosh 128K, is the original Macintosh personal computer, from Apple. It is the first successful mass-market all-in-one desktop personal computer with a graphical user interface, built-in screen, and mouse. It was pivotal in establishing desktop publishing as a general office function. The motherboard, a 9 in (23 cm) CRT monochrome monitor, and a floppy drive are in a beige case with integrated carrying handle; it has a keyboard and single-button mouse. The Macintosh was introduced by a television commercial titled "1984" during Super Bowl XVIII on January 22, 1984, and directed by Ridley Scott. Sales were strong at its initial release on January 24, 1984, at $2,495, and reached 70,000 units on May 3, 1984. Upon the release of its successor, the Macintosh 512K, it was rebranded as the Macintosh 128K. The computer's model number is M0001.