Nintendo 64 accessories are first-party Nintendo hardware—and third-party hardware, licensed and unlicensed. Nintendo's first-party accessories are mainly transformative system expansions: the 64DD Internet multimedia platform, with a floppy drive, video capture and editor, game building setup, web browser, and online service; the controller plus its own expansions for storage and rumble feedback; and the RAM-boosting Expansion Pak for big improvements in graphics and gameplay. Third-party accessories include the essential game developer tools built by SGI and SN Systems on Nintendo's behalf, an unlicensed SharkWire online service, and unlicensed cheaper counterparts to first-party items. In the fifth generation of video game consoles, the Nintendo 64 had a market lifespan from 1996 to 2002.

First-party Nintendo 64 accessories have a product code prefixed with NUS, short for "Nintendo Ultra Sixty-four".

The Nintendo 64 controller (NUS-005) features a distinctive "M"-shaped design, with a "control stick", making Nintendo the first manufacturer to include a thumbstick as a standard feature in its primary controller. While functionally similar to an analog stick, the control stick is digital, operating on the same principles as a ball mouse.

The controller includes a D-pad and ten buttons: a large A and B button, a Start button, four C-buttons (Up, Down, Left, and Right), two shoulder buttons (L and R), and a Z trigger positioned on the back. A port on the bottom of the controller allows users to connect other accessories, including the Controller Pak, the Rumble Pak, and the Transfer Pak.

The Controller Pak (NUS-004) is the console's memory card, comparable to those of the PlayStation and GameCube. Compatible games can save player data to the Controller Pak, which plugs into the bottom of the Nintendo 64 controller, as do the Rumble Pak and Transfer Pak. The Controller Pak was marketed for exchanging data between Nintendo 64 owners, because data on the game cartridge can not be transferred.

The original models from Nintendo have 32 KB of battery backed SRAM, split into 123 pages with a limitation of 16 save files, but third-party models have much more, often in the form of 4 selectable memory banks of 32 KB. Games occupy varying numbers of pages, sometimes using the entire card. It is powered by a common CR2032 battery.

Upon launch, the Controller Pak was initially useful, and even necessary for early games. Over time, the Controller Pak lost popularity to the convenience of a battery backed SRAM or EEPROM in some cartridges. Because the Nintendo 64 Game Pak format also allows saving data on supported cartridges, few first-party and second-party games use the Controller Pak. The vast majority are from third-party developers. This is most likely due to the increased production and retail costs which would have been caused by including self-contained data on the cartridge. Some games use it to save optional data that is too large for the cartridge, such as Mario Kart 64, which uses 121 of the total 123 pages for storing ghost data, or International Superstar Soccer 64, which uses the entire cartridge's space for its save data. Tony Hawk's Pro Skater uses 11 pages. Quest 64 and Mystical Ninja Starring Goemon use the Controller Pak exclusively for saved data. The Japan-only game Animal Forest uses the Controller Pak to travel to other towns. Animal Forest also had the ability to play Famicom games that were saved onto a Controller Pak. This second use was far less known, as only one game, Ice Climber, was released via this method through magazine giveaways.

Following the 1996 Christmas shopping season, Next Generation reported "impressive sales of the memory pack cartridges despite the lack of available games to take advantage of the $19.99 units".