GCD

The three letter acronym GCD may refer to:

Gongchandang, or the Communist Party of China
Greatest common divisor — in mathematics
Great circle distance — in navigation
Griffith College Dublin — private college in Ireland
Grand Comic-Book Database — database of comic book information
Global Communications Devices — supplier of semiconductor devices used in wireless networking
Gardner Carton & Douglas — a US law firm
Gaia Community Discussion — GAIA Community Discussion; a subforum on the webforum GAIA Online. Focuses on the storyline and other happenings in the world of GAIA.
Government Confidence Demonstration — conducted during weapons systems acquisition for the US Army.