A handheld personal computer (PC) is a pocket-sized computer typically built around a clamshell form factor and is significantly smaller than any standard laptop computer, but based on the same principles. It is sometimes referred to as a palmtop computer, not to be confused with Palmtop PC which was a name used mainly by Hewlett-Packard.

Most handheld PCs use an operating system specifically designed for mobile use. Ultra-compact laptops capable of running common x86-compatible desktop operating systems are typically classified as subnotebooks. The first hand-held device compatible with desktop IBM personal computers of the time was the Atari Portfolio of 1989. Other early models were the Poqet PC of 1989 and the Hewlett Packard HP 95LX of 1991 which run the MS-DOS operating system. Other DOS-compatible hand-held computers also existed. After 2000 the handheld PC segment practically halted, replaced by other forms, although later communicators such as Nokia E90 can be considered to be of the same class.

The name Handheld PC was used by Microsoft from 1996 until the early 2000s to describe a category of small computers having keyboards and running the Windows CE operating system.