"Big Iron" is a country ballad by Marty Robbins, originally released as an album track on Gunfighter Ballads and Trail Songs in September 1959, then as a single in February 1960 with the song "Saddle Tramp" as the B-side single. Members of the Western Writers of America chose it as one of the Top 100 Western songs of all time.

Big iron, as the hacker's dictionary the Jargon File defines it, "refers to large, expensive, ultra-fast computers. It is used generally for number crunching supercomputers such as Crays, but can include more conventional big commercial IBM mainframes".