Nintendo is one of the largest video game publishers in the world, producing both hardware and software. Since the release of the Nintendo Entertainment System in 1985, the company has generally been proactive to assure its intellectual property in both hardware and software is legally protected. Nintendo's protection of its properties began as early as the arcade release of Donkey Kong which was widely cloned on other platforms, a practice common to the most popular arcade games of the era. Nintendo did seek legal action to try to stop release of these unauthorized clones, but estimated they still lost in potential sales to these clones. Nintendo also fought off a claim in 1983 by Universal Pictures that Donkey Kong was a derivative element of their King Kong in Universal City Studios, Inc. v. Nintendo Co., Ltd.; notably, Nintendo's lawyer, John Kirby, became the namesake of Kirby in honor of the successful defense.
Nintendo frequently issues DMCA notices against emulators, mods, ROM hacks and fan-made games. While publications like Engadget describe these actions as "within [Nintendo's] right", the company's hostile stance is much maligned and criticised within the video game community.
Copyright circumvention Nintendo became more proactive as they entered the Famicom/NES period. Nintendo had witnessed the events of a flooded game market that occurred in the United States in the early 1980s that led to the 1983 video game crash, and with the Famicom had taken business steps, such as controlling the cartridge production process, to prevent a similar flood of video game clones. The Famicom, however, had lacked any lockout mechanics, and numerous unauthorized bootleg cartridges were made across the Asian regions. Nintendo took a step to create its "Nintendo Seal of Quality" stamped on the games it made to dissuade consumers from purchasing these bootlegs, and as it prepared the Famicom for entry to Western regions as the NES, incorporated a lock-out system that only allowed authorized game cartridges they manufactured to be playable on the system. After the NES's release, Nintendo took legal action against companies that attempted to reverse-engineer the lockout mechanism to make unauthorized games for the NES. While Nintendo was successful to prevent reverse engineering of the lockout chip in the case Atari Games Corp. v. Nintendo of America Inc., they failed to prevent devices like Game Genie from being used to provide cheat codes for players in the case Lewis Galoob Toys, Inc. v. Nintendo of America, Inc.. The Blockbuster rental chain settled with Nintendo in the Nintendo of America, Inc. v. Blockbuster Entertainment Corp. case after they began including photocopies of Nintendo's game manuals in rented games.
A unique exception was the Christian video game developer Wisdom Tree, which was an offshoot of unlicensed game developer Color Dreams who previously published NES titles without Nintendo's approval, resorting to workarounds such as a voltage spike to temporarily knock the CIC chip offline, bypassing the NES's security. Color Dreams previously faced difficulties selling their games to mainstream retailers as Nintendo threatened to cease selling games to retailers that sold unlicensed NES games. Unlike most developers of unlicensed NES games, Nintendo remained reticent and did not take legal action against Wisdom Tree, likely due to fears of a public relations backlash from parents and religious groups.
In 2021, Gary Bowser was sentenced to 40 months in prison and ordered to pay $14.5 million in restitution for his role in a Nintendo hacking scheme. Critics claim that the punishment was excessive, while others argue that it was necessary to send a message to deter other hackers and protect intellectual property rights. Bowser's recent release from jail has brought attention to the impact that the massive amount of money he owes in restitution may have on his life and livelihood, as he claims to have only been able to pay off a small fraction of the fine so far. During the hacking scheme, Bowser personally made only $320,000 in profit.
Nintendo initiated two lawsuits against users for circumventing copyright and facilitating copyright infringement in June 2024. One was against the owner of ModdedHardware, a website that sold modified Switch units and components that bypassed Nintendo's protections. Nintendo won the case and was awarded $2 million from the site owner in September 2025, as well a permanent injunction forcing the site to shut down and be transferred to Nintendo. The other was against one of the lead moderators of the Reddit subforum r/SwitchPirates, which had over 190,000 members that traded Nintendo software stripped of copyright protections. The defendant in the second claim failed to show up for initial court hearings, causing Nintendo to seek subpoenas for other members of the r/SwitchPirates group, including through Discord and Google records. By October 2025, Nintendo has discovered the identity of the Reddit moderator, and was able to win a default judgement of $4.5 million in damages from the person in September 2026.
Within the Nintendo Switch 2, Nintendo included the ability to detect the use of modified game cartridges that can be used to work around the console's copy protection, such as by storing ROM dumps of game carts; one such example being the Mig Flash. Users that had used these found that they were blocked from using any of Nintendo's online services.
Emulation Nintendo has used emulation by itself or licensed from third parties to provide means to re-release games from their older platforms on newer systems, with Virtual Console, which re-released classic games as downloadable titles, the Nintendo Classics library for Nintendo Switch Online subscribers, and with dedicated consoles like the NES and Super NES Classic Editions. Nintendo, however, has taken a hard stance against unlicensed emulation of its video games and consoles, stating that it is the single largest threat to the intellectual property rights of video game developers. A patent attorney for Nintendo, Koji Nishiura, said of the company's stance on emulation, "While you can't immediately claim that an emulator is illegal in itself, it can become illegal depending on how it's used", and cited examples of emulation disabling security features or providing links for acquiring game ROMs as cases they consider illegal. Further, Nintendo has taken action against fan-made games which have used significant facets of their IP, issuing cease & desist letters to these projects or Digital Millennium Copyright Act (DMCA)-related complaints to services that host these projects. The company has also taken legal action against those that made modchips for its hardware; notably, in 2020 and 2021, Nintendo took action against Team Xecuter which had been making modchips for Nintendo's consoles since 2013, after members of that team were arrested by the United States Department of Justice. In a related action, Nintendo sent a cease and desist letter to the organizers of the 2020 The Big House Super Smash Bros. tournament that was held entirely online due to the COVID-19 pandemic that year. Nintendo had taken issue with the tournament using emulated versions of Super Smash Bros. Melee which had included a user mod for networked play, as this would have required ripping a copy of Melee to play, an action they do not condone.
Nintendo issued Valve a DMCA request prior the release of the Dolphin emulator for Wii and GameCube games on the Steam storefront in May 2023, asserting that the inclusion of the Wii Common Key used to decrypt Wii games violated their copyright. In 2024, Nintendo took legal action against the open-source Yuzu emulator for Switch games, stating that the software violates the DMCA by enabling decryption of the encryption method used for Switch games, and that it facilitated copyright infringement of The Legend of Zelda: Tears of the Kingdom through a leaked copy that had been downloaded a million times from piracy websites prior to the game's official release. The Yuzu team settled with Nintendo, agreeing to pay $2.4 million and stopping work on Yuzu, halting distribution of the code, and turning its domains and websites over to Nintendo. As some of the Yuzu team had also worked on the Citra 3DS emulator, that project was also terminated, and its code was taken offline. Some users not associated with the Yuzu team had attempted to fork the latest builds of Yuzu before it was taken offline, taking stances to completely avoid discussions related to the encryption aspects and any software piracy. Nintendo continued to issue DMCA requests to remove source repositories as well as Discord servers established by these users to discuss their forks' development. In October, Nintendo forced Ryujinx, an open-source alternative to Yuzu, to shut down its activities, broadening its crackdown on Nintendo Switch emulation. The developers were contacted by Nintendo to stop working on the project, remove the organization and all its related assets. Nintendo took more action to issue takedowns of Yuzu offshoots from GitHub in August 2026.
Fan games Fan games that reuse or recreate Nintendo assets also have been targeted by Nintendo typically through cease and desist letters or DMCA-based takedown to shut down these projects. Full Screen Mario, a web browser-based version of Super Mario Bros., was shut down in 2013 after Nintendo issued a cease and desist letter. Other notable fan projects that have been taken down include Pokémon Uranium, a fan game based on the Pokémon series in 2016, Super Mario 64 Online, an online multiplayer version of Super Mario 64 in 2017, and Metroid Prime 2D, a demake of Metroid Prime, in 2021. Nintendo has defended these actions as necessary to protect its intellectual property, stating that "Nintendo respects the intellectual property rights of others", but also that they want to protect characters, trademarks and other content in regards to their established franchises. In some cases, the developers of these fan games have repurposed their work into new projects. In the case of No Mario's Sky, a mashup of Super Mario Bros. and No Man's Sky, after Nintendo sought to terminate the project, the Mario content was stripped and the game was renamed as DMCA's Sky.
In 2016, Nintendo issued DMCA takedowns for hundreds of fan games hosted on the platform Game Jolt, as well as others off-site, such as the unofficial Metroid II remake, AM2R. This followed another takedown request for AM2R issued earlier that year. Two of the affected games, Pokémon Uranium and AM2R, had been nominated for The Game Awards that year, and were subsequently removed. Later the same year, Pokémon Prism was also shut down. In 2020, an in-development Mother 3 fan sequel previously dubbed Mother 4 was renamed Oddity, and its references to the series removed, in order to prevent the game from being taken down. In 2021, Nintendo of America's legal team issued a mass DMCA takedown of 379 games removed out from Game Jolt. Many of the games' developers and fans have been taken it by surprise, although Nintendo's mention of advertisement revenue being used on the games' page made the reasoning behind the takedowns. An "ambitious" Metroid-based fan game, Metroid Prime 2D, which had been in development for 15 years, was taken down by Nintendo in August 2021, four months after a demo was released.