Activision Publishing, Inc. is an American video game publisher based in Santa Monica, California. It serves as the publishing business for its parent company, Activision Blizzard, and consists of several subsidiary studios.

In early 1979, Atari's marketing department circulated a memo listing the best-selling cartridges from the previous year to help guide game ideas. David Crane noted that the games he was fully responsible for had brought in over $20 million for the company but he was still only receiving a $20,000 salary. Out of a development staff of thirty-five, four programmers (David Crane, Larry Kaplan, Alan Miller and Bob Whitehead), had produced games that had accounted for 60% of Atari's sales. The four made the decision to soon leave Atari and start their own business, but were not sure how to go about it. In 1979, the concept of third-party developers did not exist, as software for video game consoles were published exclusively by makers of the systems for which the games were designed; thus the common thinking was that to make console games, one needed to make a console first. The four decided to create their own independent game development company. Activision was formally founded on October 1, 1979, with Levy serving as CEO. The company was initially named "Computer Arts, Inc." while they considered a better title. The founders had thought of the name VSync, Inc., but feared that the public would not understand or know how to say it. Levy suggested combining "active" and "television" to come up with Activision.

After video game crash of 1983, Miller and Whitehead left in 1984 due to the large devaluation of their stock and went to form Accolade.

Looking to expand further, Activision acquired, through a corporate merger, the struggling text adventure pioneer Infocom in June 1986. This acquisition was spearheaded by Levy, who was a big fan of Infocom's titles and felt the company was in a similar position as Activision. About six months after the "Infocom Wedding", Activision's board decided to replace Levy with Bruce Davis. Davis was against the purchase of Infocom from the start and was heavy-handed in its management, and even attempted to seek a lawsuit to recover their purchase from Infocom's shareholders. Crane also found Davis difficult to work with and was concerned with how Davis managed the closure of Imagic, one of the third-party development studios formed in Activision's success in 1981. Crane left Activision in 1986 and helped Garry Kitchen found Absolute Entertainment. In late 1986, Activision adopted the Electric Dreams brand, usually used for British software, for titles outside of English for the American market.

In 1988, Activision began involvement in software besides video games, such as business applications. As a result, Activision changed its corporate name to Mediagenic to better represent all of its activities. Mediagenic consisted of four groups:

• Activision: video game publisher for various platforms, notably the Nintendo Entertainment System, Master System, Atari 7800, Atari ST, Commodore 64, and Amiga

• Infocom: developer of interactive fiction games

• Gamestar: initially an independent company but purchased by Activision in 1986. Specialized in sports video games

• Ten Point O: business application software

In 1989, after several years of losses, Activision closed down the Infocom studios.During this period Mediagenic, via Activision, secured the rights to distribute games from Cyan Worlds. The first game published by Activision from Cyan was The Manhole, on CD-ROM for personal computers, the first major game distributed in this format.

Davis' management of Mediagenic failed to produce a profitable company; in 1991, Mediagenic reported a loss of $26.8 million on only $28.8 million of revenue and had over $60 million in debt. Cyan severed their contract with Activision, and turned to Broderbund for publishing, including what would become one of the most significant computer games of the 1990s, Myst.

Bobby Kotick had become interested in the value of the video game industry following the crash and was drawn to buy out Mediagenic not for its current offerings but for the Activision name, given its past successes with Pitfall!, with hopes to restore Activision to its former glory. Crane said that Kotick has recognized the Activision brand name could be valued around $50 million and rather than start a new company and spend that amount to obtain the same reputation, he saw the opportunity to buy the failing Mediagenic at a bargain price and gain Activision's reputation with minimal cost. Kotick and additional investors bought Mediagenic for approximately $500,000 in 1991. This group of investors included real estate businessman Steve Wynn and Philips Electronics.

Kotick became CEO of Mediagenic on its purchase and made several immediate changes: He let go of all but 8 of the companies' 150 employees, performed a full restructuring of the company, developed a bankruptcy restructuring plan, and reincorporated the company in Los Angeles, California. After Mediagenic fulfilled on the bankruptcy plan, by the end of 1992, Kotick renamed Mediagenic to the original Activision name. The new Activision went public in October 1993, raising about $40 million, and was listed on NASDAQ under its new ticker symbol ATVI.

With several of its own successfully developed games helping to turn a profit, Kotick led Activision to start seeking acquisitions of video game development studios, guided by market surveys to determine what areas of content to focus on. It is estimated that between 1997 and 2008, Activision made 25 acquisitions, several for undisclosed amounts. Some of the key acquisitions and investments made by Activision in this period include:

• Raven Software: Around 1997, Raven's founders Brian and Steve Raffel felt the need to seek a parent company. By the end of 1997, Activision acquired Raven as one of its first subsidiaries under Kotick. The acquisition price was $12 million.

• Neversoft: Prior to its acquisition in 2000, Activision had arranged a development deal with Neversoft to re-develop Apocalypse, a title that failed to be completed within Activision. Subsequently, Activision had Neversoft work on a prototype for a skateboarding game, which would end up becoming the first in the Tony Hawk's series of skateboarding video games. Tony Hawk's Pro Skater was a critical success, leading Activision to acquire Neversoft in April 2000. After eight games, the series has brought in $1.6 billion.

• Infinity Ward: Activision acquired the studio for $5 million in January 2003, and later publish their first title, Call of Duty. The Call of Duty series has since seen nearly yearly releases and as of 2016 had sold more than 250 million units and brought in more than $12 billion in revenue.

• Treyarch: Activision used Treyarch to assist in further Tony Hawk games as well as to develop titles using Activision's license of Marvel's Spider-Man. Activision acquired the studio in 2001 for about $20 million.

• Grey Matter Studios: Gray Matter began work in 1999 on Return to Castle Wolfenstein, in conjunction with Nerve Software and oversight by id Software who owned the Castle Wolfenstein IP. Activision, the game's publisher, acquired a portion of Gray Matter's stock during this time. Return to Castle Wolfenstein was a critical and financial success, and led Activision to acquire the remaining shares of Gray Matter in 2002 for about $3.2 million, with the intent to help Infinity Ward expand out the Call of Duty franchise. In 2005, Activision made the decision to merge the smaller Gray Matter into the larger Treyarch to put their combined talents towards Call of Duty 3.

• RedOctane: Around 2005, Red Octane was co-developing Guitar Hero, a console game based on the arcade game GuitarFreaks, with Harmonix. Guitar Hero was a major success. Activision purchased RedOctane for nearly $100 million in June 2006. The series has since earned more than $2 billion in revenues.

• Toys for Bob: Activision purchased the studio in 2005, and had given them work on some of the Tony Hawk's games as well as other licensed properties. Following Activision's merger with Vivendi, Activision gained the Spyro intellectual property and assigned Toys for Bob to develop the series in a new direction, leading to the toys-to-life Skylanders series.

On June 16, 2000, Activision reorganized as a holding company, Activision Holdings, to manage Activision and its subsidiaries more effectively. Activision changed its corporate name from "Activision, Inc." to "Activision Publishing, Inc.", while Activision Holdings took Activision's former "Activision, Inc." name. Activision Publishing became a wholly owned subsidiary of Activision, which in turn became the publicly traded company, with all outstanding shares of capital stock converted.

In 2003, Activision's founders were given the Game Developers Choice "First Penguin" award, reflecting their being the first successful third-party developer in the video game industry.

While Activision was highly successful with its range of developers and successful series, Kotick was concerned that they did not have a title for the growing massively multiplayer online market, which presented the opportunity for continued revenues from subscription models and microtransactions instead of the revenue from a single sale. Around 2006, Kotick contacted Jean-Bernard Lévy, the new CEO of Vivendi, a French media conglomerate. Vivendi had a games division, Vivendi Games, that was struggling to be viable at the time, but its principal feature was that it owned Blizzard Entertainment and its highly successful World of Warcraft game, which was drawing in $1.1 billion a year in subscription fees. Vivendi Games also owned Sierra Entertainment. Kotick met with Blizzard's president Mike Morhaime, and learned that Blizzard also had a successful inroad into getting their games into China, a potentially lucrative market. Given this potential opportunity, Kotick agreed to the merger. Activision's board signed on to the merger by December 2007. The merger was completed in July 2008. The new company was called Activision Blizzard and was headed by Kotick, while Vivendi maintained a 52% share in the company. The new company was estimated to be worth US$18.9 billion, ahead of Electronic Arts, which was valued at US$14.1 billion.

Activision Publishing remains a subsidiary of Activision Blizzard following the merger, and is responsible for developing, producing, and distributing games from its internal and subsidiary studios. Eric Hirshberg was announced as Activision Publishing's CEO in 2010.

Activision Publishing established Sledgehammer Games in November 2009.

In February 2010, Activision Blizzard reported significant losses in revenue stemming from a slow down in Guitar Hero sales and from its more casual games. Subsequently, Activision Publishing shuttered RedOctane, Luxoflux and Underground Development as well as laid off about 25% of the staff at Neversoft. Within the same year, Activision shuttered Budcat Creations in November 2010, and Bizarre Creations in February 2011.

Hirshberg left the CEO position in March 2018.

With the acquisition of Activision Blizzard by Microsoft in October 2023, Activision Blizzard as a whole, including the Activision Publishing subdivision, became a separate division under the Microsoft Gaming arm of Microsoft.