CAT6 is an Ethernet cable standard defined by the Electronic Industries Association and Telecommunications Industry Association (commonly known as EIA/TIA). CAT6 is the sixth generation of twisted pair Ethernet cabling.

CAT6 cable contains four pairs of copper wire like the previous generation CAT5. Unlike CAT5, however, CAT6 fully utilizes all four pairs. CAT6 supports Gigabit Ethernet speeds up to 1 gigabit per second (Gbps) and supports communications at more than twice the speed of CAT5e, the other popular standard for Gigabit Ethernet cabling. An enhanced version of CAT6 called CAT6a supports up to 10 Gbps speeds.

As with all other types of twisted pair EIA/TIA cabling, individual CAT6 cable runs are limited to a maximum recommended length of 100m (328 feet). Printing along the length of the cable sheath identifies it as CAT6.