The British Rail Class 03 locomotive was, together with the similar Class 04, one of British Railways' most successful 0-6-0 diesel-mechanical shunters. 230 were built at Doncaster and Swindon works between 1957 and 1962, and were numbered D2000-D2199 and D2370-D2399 (later 03004 to 03399). D2370 and D2371 were used as departmental locomotives and originally numbered 91 and 92 respectively.

Most remaining examples are now in industrial use or preservation.