The Macintosh II is a personal computer designed, manufactured, and sold by Apple Computer from March 1987 to January 1990. Based on the Motorola 68020 32-bit CPU, it is the first Macintosh supporting color graphics. When introduced, a basic system with monitor and 20 MB hard drive cost US$5,498 (equivalent to $13,110 in 2021). With a 13-inch color monitor and 8-bit display card the price was around US$7,145 (equivalent to $17,040 in 2021). This placed it in competition with workstations from Silicon Graphics, Sun Microsystems, and Hewlett-Packard.

The Macintosh II was the first computer in the Macintosh line without a built-in display; a monitor rested on top of the case like the IBM Personal Computer and Amiga 1000. It was designed by hardware engineers Michael Dhuey (computer) and Brian Berkeley (monitor) and industrial designer Hartmut Esslinger (case).

Eighteen months after its introduction, the Macintosh II was updated with a more powerful CPU and sold as the Macintosh IIx. In early 1989, the more compact Macintosh IIcx was introduced at a price similar to the original Macintosh II, and by the beginning of 1990 sales stopped altogether. Motherboard upgrades to turn a Macintosh II into a IIx or Macintosh IIfx were offered by Apple.