MorphOS is an AmigaOS-like operating system designed for Power and PowerPC based computers. The core, based on the Quark microkernel, is proprietary, although several libraries and other parts are open source, such as the Ambient desktop.

The project began in 1999 and it was produced for the Pegasos computer, as well as PowerUP accelerator equipped Amiga computers, and a series of Freescale development boards that use the Genesi firmware, including the Efika and mobileGT. Since then MorphOS has been ported to Apple's Mac mini, eMac, Power Mac G4 and limited support for Power Mac G5. It is binary compatible with software written for Motorola 68k-based Amiga computers.

The project began in 1999, based on the Quark microkernel. The earliest versions of MorphOS ran only via PPC accelerator cards on the Amiga computers, and required portions of AmigaOS to fully function. A collaborative effort between the companies bPlan (of which the lead MorphOS developer is a partner) and Thendic-France in 2002 resulted in the first regular, non-prototype production of bPlan-engineered Pegasos computers capable of running MorphOS or Linux. Thendic-France had financial problems and folded; however, the collaboration continued under the new banner of "Genesi". A busy promotional year followed in 2003, with appearances at conventions and exhibitions in several places around the world, including the Consumer Electronics Show (CES) in Las Vegas.

After some bitter disagreements within the MorphOS development team in 2003 and 2004, culminating with accusations by a MorphOS developer that he and others had not been paid, the Ambient desktop interface was released under GPL and is now actively developed by the Ambient development team. Subject to GPL rules, Ambient continues to be included in the commercial MorphOS product. An alternative MorphOS desktop system is Scalos.

Developed for PowerPC CPUs from Freescale and IBM, it also supports the original AmigaOS Motorola 68000 series (68k, MC680x0) applications via proprietary task-based emulation, and most AmigaOS PPC applications via API wrappers. It is API compatible with AmigaOS 3.1 and has a GUI based on the Magic User Interface (MUI).

Besides the Pegasos version of MorphOS, there is a version for Amiga computers equipped with PowerUP accelerator cards produced by Phase5. This version is free, as is registration. If unregistered, it slows down after each two-hour session. PowerUP MorphOS was most recently updated on 23 February 2006; however, it does not exceed the feature set or advancement of the Pegasos release.

A version of MorphOS for the Efika, a very small mainboard based on the ultra-low-power MPC5200B processor from Freescale, has been shown at exhibitions and user gatherings in Germany. Current (since 2.0) release of MorphOS supports the Efika.

MorphOS can run any system friendly Amiga software written for 68k processors. Also it is possible to use 68k libraries or datatypes on PPC applications and vice versa. It also provides compatibility layer for PowerUP and WarpUP software written for PowerUP accelerator cards. The largest repository is Aminet with over 75,000 packages online with packages from all Amiga flavors including music, sound, and artwork. MorphOS-only software repositories are hosted at MorphOS software, MorphOS files and MorphOS Storage. MorphOS is delivered with several desktop applications in the form of pre-installed software.