SkiFree is a single-player skiing computer game created by Chris Pirih and released with Microsoft Entertainment Pack 3 for Windows 3.0 in October 1991. The player controls a skier on a mountain slope, avoiding obstacles while racing against time or performing stunts for points, depending on the game mode.

SkiFree was well-received upon release, with critics focusing on its simplicity and graphics. The game was later ported to Game Boy Color and iOS. Pirih also released a free, updated 32-bit Windows version in 2005 after rediscovering the original source code. SkiFree remains popular among the gaming community and is often remembered for its Abominable Snowman, which pursues the player after they finish a full run.

In 2020, Microsoft released Surf, a game included with Microsoft Edge heavily inspired by SkiFree. A winter skin where the player skis instead of surfs and must run from the SkiFree Abominable Snowman was added to the game in 2021.

SkiFree is a casual single-player sports simulator wherein the player uses the keyboard or the mouse to control a skier across a white background representing snow on a mountainside. The object of the game is to ski down an endless slope and avoid the obstacles (trees, stumps, dogs, etc.). The player can also opt to partake in three modes: slalom, freestyle, and tree slalom. In slalom, players must properly ski around flags in an attempt to complete the run with the shortest time possible. Tree slalom adds obstacles to the slalom run. In freestyle, players ski downhill and jump off ramps while racking up points by performing tricks. Deductions are imposed for colliding into obstacles or failing to land properly after a stunt. When the player passes the 2,000-meter mark, the Abominable Snowman appears and starts to chase the player, eating them when it catches them.

While SkiFree creator Chris Pirih was a student at the University of Puget Sound, he wrote a text-based game called Ski in Fortran for the VAX/VMS operating system, inspired by Activision's Atari 2600 game Skiing. Later, as a programmer for Microsoft he was writing programming utilities used in the development of software such as Microsoft Word and Microsoft Excel. He had been focused on developing for the OS/2 operating system, but in 1991 decided to learn to write for the newly released Windows 3.0, and so created a new version of his skiing game in the programming language C, replacing the text-based environment with graphics. He called the game WinSki, and added exploitable, fanciful elements to demonstrate the new operating system's functionality, such as staining the snow yellow after crashing into numerous dogs and certain tree stumps transforming into mushrooms when skied on backwards.

Although he developed it on his home computer for his own education and entertainment, WinSki attracted the attention of a program manager for the Microsoft Entertainment Pack (MEP) when he noticed Pirih playing it at work. At that time, the first MEP had become so successful that the MEP team was designing two more. In October 1991, Microsoft shipped MEPs 2 and 3 for Windows 3.0, the latter pack containing Pirih's game renamed and marketed by Microsoft as SkiFree. It was distributed on Verbatim 3.5-inch GameSampler floppy disks, bundled with packs of 10 other blank floppy disks in the early 1990s.

Since its debut, SkiFree has seen several ports and rereleases. SkiFree was featured in The Best of Microsoft Entertainment Pack in 1994, and was also one of seven games included in the Game Boy Color version of the compilation released in May 2001. On April 4, 2005, Pirih announced the creation and release of a 32-bit version of SkiFree on his website for free, after rediscovering the game's source code that year, which he had lost when he was developing a second version of the game in 1993, leading to its abandonment for other projects.

In January 2013, mobile games developer GearSprout developed and released iOS ports of SkiFree and Rodent's Revenge. The company had already released SkeeFree, a skiing game with identical assets. In a Destructoid interview with GearSprout co-founder Tommy Tornroos, he explained that the company contacted Microsoft about porting their titles, and Microsoft responded that they were "no longer claiming rights" to them. However, the SkiFree trademark was reserved by an unspecified entity, leading to the release of SkeeFree. The SkiFree trademark later expired, and the name of the GearSprout game was updated as SkiFree when it was released alongside Rodent's Revenge. SkiFree was included in The Windows 3.x Showcase and uploaded to the Internet Archive in February 2016, becoming the most popular item on the website within a week.