Mac OS X Panther (version 10.3) is the fourth major release of macOS, Apple's desktop and server operating system.

The main features of Panther included a refined Aqua theme, Exposé, Fast user switching, and a new Finder.

Panther also included Safari as its default browser, as a change from Internet Explorer in Jaguar.

Panther's system requirements are:[4] Video conferencing requires: Because a New World ROM was required for Mac OS X Panther, certain older computers (such as beige Power Mac G3s and 'Wall Street' PowerBook G3s) were unable to run Panther by default.

Apple advertised that Mac OS X Panther had over 150 new features, including: Panther was Apple's earliest version of Mac OS X that supported WPA and WPA2 security for wireless networks (with the AirPort 4.2 software update).