Palm OS was a mobile operating system initially developed by Palm, Inc., for personal digital assistants (PDAs) in 1996. Palm OS was designed for ease of use with a touchscreen-based graphical user interface. It was provided with a suite of basic applications for personal information management. Later versions of the OS were extended to support smartphones. The software appeared on the company's line of Palm devices while several other licensees have manufactured devices powered by Palm OS.

Palm, Inc., was an American company that specialized in manufacturing personal digital assistants (PDAs) and developing software. Palm designed the PalmPilot, the first PDA successfully marketed worldwide, and was known for the Treo 600, one of the earlier successful smartphones. Palm developed the Palm OS software for PDAs and smartphones released under its line of Palm-branded devices and also licensed to other PDA manufacturers.