Palm OS是一种32位的嵌入式操作系统，用于掌上电脑。此系统是3Com公司的Palm Computing 部开发的。(Palm Computing已经独立成一家公司。) Palm OS与同步软件HotSync结合可以使掌上电脑与PC机上的信息实现同步，把台式机的 功能扩展到了手掌上。一些其他的公司也获得了生产基于Palm OS的PDA的许可，如SONY公司，Handspring公司。

在2001年，基于Palm OS的掌上电脑主要是3Com的系列产品，如Palm IIIx，Palm V，Palm VII, IBM WorkPad c3用的也是Palm OS。Sony等公司也获得了Palm Computing的许可，将开发 基于Palm OS的掌上电脑。

Palm OS (also known as Garnet OS) is 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 is provided with a suite of basic applications for personal information management. Later versions of the OS have been extended to support smartphones. Several other licensees have manufactured devices powered by Palm OS.