"The Age of Steel" is the sixth episode of the second series of the British science fiction television programme Doctor Who. It was first broadcast on BBC One on 20 May 2006 and is the second part of a two-part story. The first part, "Rise of the Cybermen", was broadcast on 13 May.

The second series of British science fiction programme Doctor Who began on 25 December 2005 with the Christmas special "The Christmas Invasion". A regular series of thirteen episodes was broadcast weekly in 2006, starting with "New Earth" on 15 April and concluding with "Doomsday" on 8 July. In addition, two short special episodes were produced; a Children in Need special and an interactive episode, as well as thirteen minisodes titled Tardisodes. It is the second series of the revival of the show, and the twenty-eighth season overall.