Mac OS X version 10.4 “Tiger” is the fifth major release of Mac OS X, Apple’s desktop and server operating system for Macintosh computers. Tiger was released to the public on April 29 2005 as the successor to Mac OS X v10.3 “Panther”, which was released 18 months earlier, and was superceded by Mac OS X v10.5 “Leopard” on October 26 2007, after 30 months, making Mac OS X v10.4 the longest running version of the Mac OS X operating system. Some of the new features include a fast searching system called Spotlight, a new version of the Safari web browser, Dashboard, a new ‘Unified’ theme, and improved support for 64-bit addressing on Power Mac G5s.

Mac OS X v10.4 “Tiger” was included with all new Macintosh computers, and was also available as an upgrade for existing Mac OS X users, or users of supported pre-Mac OS X systems. The server edition, Mac OS X Server 10.4, was also available for some Macintosh product lines. Tiger is also the first version of any released Apple operating system to work on Apple-Intel architecture machines (Apple machines using x86 processors.) The Apple TV, as released in March 2007, ships with a customized version of Mac OS X v10.4 branded "Apple TV OS" that replaces the usual graphical user interface with an updated version of Front Row.

Six weeks after its official release, Apple had delivered 2 million copies of Tiger, representing 16 % of all Mac OS X users. Apple claimed that Tiger was the most successful Apple OS release in the company’s history. At the World Wide Developers Conference on June 11, 2007, Apple CEO Steve Jobs announced that out of the 22 million OS X users, more than 67 % were using Tiger.