The Game Link Cable, also known as Video Link in early versions, is an accessory for the Game Boy line of handheld consoles. Introduced in 1989 alongside the original Game Boy, it was revised over four generations with varying degrees of backward compatibility. The cable enables data transfer and multiplayer gaming between up to four devices, supporting head-to-head competition, cooperative play, item exchanges, and unlockable features, depending on the game. The cable could also connect the console to external peripherals, most notably the Game Boy Printer. The port on Game Boy consoles is labeled "EXT" for Extension connector.

The Game Link Cable was championed by Satoru Okada, assistant director of Nintendo Research & Development 1, the team behind the Game Boy. In the early 1980s, Okada had worked on Computer Mah-jong Yakuman, a Nintendo handheld electronic game that utilized cable communication between two devices. Convinced that a similar feature could enhance the Game Boy, he strongly advocated for its inclusion. Despite skepticism from the team, who feared it would be too complicated and underutilized, Okada pushed forward and personally developed the Game Link Cable technology.

The first-generation Game Link Cable (model DMG-04) launched alongside the original Game Boy. Featuring "large" connectors on both ends, it linked two original Game Boy consoles for compatible multiplayer games identified by an icon on packaging and cartridges.

Yakuman, one of the four Japanese launch titles for the Game Boy was the first to utilize the Game Link Cable for multiplayer functionality.

Some games, such as F-1 Race, supported up to four players but required the Game Boy Four Player Adapter (model DMG-07) and three Game Link Cables.

The second generation started with the release of the Game Boy Pocket which used a much smaller Game Link connector than those used on the original Game Boy. Although the pin assignment and basic port shape remained the same, its much smaller size necessitated the release of new Game Link Cables. The Game Boy Light (a backlit Game Boy Pocket only released in Japan), Super Game Boy 2, and the Game Boy Color also used the same link cable port design.

The Game Boy Color offered a "high-speed" mode that enabled data transmission over the Game Link Cable at up to 512 kilobits per second, 64 times faster than the 8 kbit/s speed of earlier monochrome Game Boy models.

The second generation Game Link Cables came in a few varieties, but each serves the same purpose. The first was called the Game Boy Pocket Game Link Cable (model MGB-008) features the smaller second generation connectors on both ends. The second is called the Universal Game Link Cable (model MGB-010) and featured the smaller second generation connector on one end, and the cable splits into both a second generation and first generation connector at the other end (although only one connector at this end can be used at any given time). This link cable was included with the Game Boy Printer in the US and Europe but does not appear to have been available to buy separately. The third was called the Game Boy Color Game Link Cable (model CGB-003) and was functionally identical to the MGB-008.