HP webOS is a mobile operating system based on a Linux kernel, initially developed by Palm, which was later acquired by Hewlett-Packard. The official name is webOS, uncapitalised, but WebOS is also used.

WebOS was introduced by Palm in January 2009. Various versions of webOS have been featured on several devices, including Pre, Pixi, and Veer phones and the HP TouchPad tablet.

WebOS was introduced by Palm in January 2009 as the successor to Palm OS. The first webOS device was the original Palm Pre, released on Sprint in June 2009. The Palm Pixi followed. Upgraded "Plus" versions of both Pre and Pixi were released on Verizon and AT&T.

In April 2010, HP acquired Palm; webOS was described as a key asset and motivation for the purchase. The $1.2 billion acquisition finalized in June. HP indicated its intention to develop the webOS platform for use in multiple new products, including smartphones, tablet computers and printers.

In February, 2011, HP announced that it would use webOS as the universal platform for all its devices. However, HP also made the decision that the Palm Pre, Palm Pixi, and the "Plus" revisions would not receive over-the-air updates to webOS 2.0, despite a previous commitment to an upgrade "in coming months." HP announced several new webOS devices, including the HP Veer and HP Pre 3 smartphones, running webOS 2.2, and the HP TouchPad, a tablet computer released in July 2011 that runs webOS 3.0.