Gigabit Ethernet is a term describing various technologies for implementing Ethernet networking at a nominal speed of one gigabit per second.

Gigabit Ethernet is supported over both optical fiber and twisted pair cable. Physical layer standards include 1000BASE-T, 1Gbps over cat-5e copper cabling and 1000BASE-SX for short to medium distances over fibre.

Whilst it is currently (as of 2002) deployed in high-capacity backbone network links (for instance, on a high-capacity campus network) its speed is largely not yet required for small network installations.

It is no longer the fastest Ethernet standard, with the ratification of 10 Gigabit Ethernet in 2002.