The Macintosh (mainly Mac since 1998) is a family of personal computers designed, manufactured, and sold by Apple Inc. (originally as Apple Computer, Inc.) since January 1984.

The original Macintosh is the first successful mass-market all-in-one desktop personal computer to have featured a graphical user interface, built-in screen, and mouse. Apple sold the Macintosh alongside its popular Apple II, Apple IIGS, Apple III, and Apple Lisa families of computers until the other models were discontinued in the 1990s.

Early Macintosh models were relatively expensive, hindering competitiveness in a market dominated by the much cheaper Commodore 64 for consumers, as well as the IBM Personal Computer and its accompanying clone market for businesses, although they were less expensive than the Xerox Alto and other computers with graphical user interfaces that predated the Mac, except Atari ST. Macintosh systems were successful in education and desktop publishing, making Apple the second-largest PC manufacturer for the next decade. In the early 1990s, Apple introduced the Macintosh LC II and Color Classic which were price-competitive with Wintel machines at the time.

However, the introduction of Windows 3.1 and Intel's Pentium processor, which beat the Motorola 68040 used in then-current Macintoshes in most benchmarks, gradually took market share from Apple, and by the end of 1994 Apple was relegated to third place as Compaq became the top PC manufacturer. Even after the transition to the superior PowerPC-based Power Macintosh line in the mid-1990s, the falling prices of commodity PC components, poor inventory management with the Macintosh Performa, and the release of Windows 95 contributed to continued decline of the Macintosh user base.

Upon his return to the company, Steve Jobs led Apple to consolidate the complex line of nearly twenty Macintosh models in mid-1997 (including models made for specific regions) down to four in mid-1999: the Power Macintosh G3, iMac G3, 14.1" PowerBook G3, and 12" iBook. All four products were critically and commercially successful due to their high performance, competitive prices, and aesthetic designs, and helped return Apple to profitability.

Around this time, Apple phased out the Macintosh name in favor of "Mac", a nickname that had been in common use since the development of the first model. After their transition to Intel processors in 2006, the complete lineup was Intel-based. This changed in 2020 when the M1 chip was introduced to the MacBook Air, entry level MacBook Pro and Mac Mini.

Its current lineup includes four desktops (the all-in-one iMac and the desktop Mac Mini, Mac Studio, and Mac Pro), and two notebooks (the MacBook Air and MacBook Pro). Its Xserve server was discontinued in 2011 in favor of the Mac Mini and Mac Pro.

Apple has developed a series of Macintosh operating systems. The first versions initially had no name but came to be known as the "Macintosh System Software" in 1988, "Mac OS" in 1997 with the release of Mac OS 7.6, and retrospectively called "Classic Mac OS". Apple produced a Unix-based operating system for the Macintosh called A/UX from 1988 to 1995, which closely resembled contemporary versions of the Macintosh system software. Apple does not license macOS for use on non-Apple computers, however, System 7 was licensed to various companies through Apple's Macintosh clone program from 1995 to 1997. Only one company, UMAX Technologies, was legally licensed to ship clones running Mac OS 8.In 2001, Apple released Mac OS X, a modern Unix-based operating system which was later rebranded to simply OS X in 2012, and then macOS in 2016. Its final version was macOS Catalina, as Apple went on to release macOS Big Sur in 2020. The current version is macOS Monterey, first released on June 7, 2021. Intel-based Macs can run third party operating systems such as Linux, FreeBSD, and Microsoft Windows without modification to the operating system with the aid of Boot Camp or third-party software, as opposed to PowerPC and Apple Silicon Macs, for which a special built version of the operating system is needed (such as Adlie Linux or Asahi Linux for PowerPC and Apple Silicon respectively). Volunteer communities have customized Intel-based macOS to run illicitly on non-Apple computers.

The Macintosh family of computers has used a variety of different CPU architectures since its introduction. Originally they used the Motorola 68000 series of microprocessors. In the mid-1990s they transitioned to PowerPC processors, and again in the mid-2000s they began to use 32- and 64-bit Intel x86 processors. Apple began transitioning CPU architectures to its own ARM based Apple silicon for use in the Macintosh beginning in 2020.

Apple Inc. is an American multinational technology company that specializes in consumer electronics, software and online services. Apple is the largest information technology company by revenue (totaling US$365.8 billion in 2021) and, as of January 2021, it is the world's most valuable company, the fourth-largest personal computer vendor by unit sales and second-largest mobile phone manufacturer. It is one of the Big Five American information technology companies, alongside Alphabet, Amazon, Meta, and Microsoft.

Apple was founded as Apple Computer Company on April 1, 1976, by Steve Jobs, Steve Wozniak and Ronald Wayne to develop and sell Wozniak's Apple I personal computer. It was incorporated by Jobs and Wozniak as Apple Computer, Inc. in 1977 and the company's next computer, the Apple II became a best seller. Apple went public in 1980, to instant financial success. The company went onto develop new computers featuring innovative graphical user interfaces, including the original Macintosh, announced in a critically acclaimed advertisement, "1984", directed by Ridley Scott. By 1985, the high cost of its products and power struggles between executives caused problems. Wozniak stepped back from Apple amicably, while Jobs resigned to found NeXT, taking some Apple employees with him.

As the market for personal computers expanded and evolved throughout the 1990s, Apple lost considerable market share to the lower-priced duopoly of the Microsoft Windows operating system on Intel-powered PC clones (also known as "Wintel"). In 1997, weeks away from bankruptcy, the company bought NeXT to resolve Apple's unsuccessful operating system strategy and entice Jobs back to the company. Over the next decade, Jobs guided Apple back to profitability through a number of tactics including introducing the iMac, iPod, iPhone and iPad to critical acclaim, launching memorable advertising campaigns, opening the Apple Store retail chain, and acquiring numerous companies to broaden the company's product portfolio. Jobs resigned in 2011 for health reasons, and died two months later. He was succeeded as CEO by Tim Cook.

Apple became the first publicly traded U.S. company to be valued at over $1 trillion in August 2018, then $2 trillion in August 2020, and most recently $3 trillion in January 2022. The company sometimes receives criticism regarding the labor practices of its contractors, its environmental practices, and its business ethics, including anti-competitive practices and materials sourcing. Nevertheless, the company enjoys a high level of brand loyalty, and is ranked as one of the world's most valuable brands.