A portable computer is a computer that is designed to be moved from one place to another and includes a display and keyboard. Portable computers, by their nature, are microcomputers. Portable computers, because of their size, are also commonly known as 'Lunchbox' or 'Luggable' computers. Can also be called a 'Portable Workstation' or 'Portable PC'.

The principle advantage of a Portable Computer versus a laptop or other mobile computer is the use of standard motherboards or backplanes providing plug-in slots for add-in cards. This allows mission specific cards such as test, A/D, or communication protocol (IEEE-488, 1553) to be installed. Portable Computers also provide for more disk storage by using standard 3-1/2" drives and providing for multiple drives.

Xerox NoteTaker, developed in 1976 at Xerox PARC, was the precursor to portable computers, though it remained a prototype and did not enter production.

The first portable computer was manufactured in 1979 by GM Research, a small company in Santa Monica, California. The machine which was designed and patented (US Patent No. 4,294,496) by James Murez was first delivered to The Computer Store, Santa Monica, Ca in mid 1977. It was called the Micro Star and later changed the name to The Small One. Although Xerox claims to have designed the first such system, the machine by Murez predated anything on the market or that had been documented in any publication at the time - hence the patent was issued. As early as 1979 the U.S. Government was contracting to purchase these machines. Other major customers included Sandia Labs, General Dynamics, BBN (featured on the cover of their annual report in 1980 as the C.A.T. system) and several dozen private individuals and companies around the world. In 1979, Osborn viewed the machine along with several hundred other visitors at the first computer show that was sponsored by the IEEE Westec in Los Angeles. Later that year the machine was also shown at the first Comdex show.

The first mass-produced portable computer was the Osborne 1, developed by Adam Osborne, which owed much to the NoteTaker's design. Another early portable computer released in 1982 was the Kaypro. In January 1983, the first IBM PC compatible portable computer (and indeed the first 100% IBM PC compatible, or "clone," of any kind) was the Compaq Portable. The first full-color portable computer was the Commodore SX-64 in January 1984. Apple, Inc. introduced a portable Apple IIc in April 1984, but would not release a Macintosh Portable until 1989, though the original Macintosh was by its compact design, technically a portable.