The Expansion Pak is a RAM add-on for the Nintendo 64 game console, released in 1998. It gives the N64 8, as opposed to 4, MB of contiguous main memory. This allows for greater screen resolution, more detailed graphics, and a higher framerate. The Nintendo 64DD was the initial reason the pak was made, because the extra RAM would be required to run the add-on.

The only games that require its use are The Legend of Zelda: Majora's Mask and Donkey Kong 64 (originally the Expansion Pak was included with purchase of the latter). Also, without the add-on, most of Perfect Dark is inaccessible.

It was utilized for more minor improvements early on, as in Turok 2, Vigilante 8 and Star Wars: Rogue Squadron.