Class 12 or 12 class may refer to:
Railroading British Rail Class 12, a British diesel locomotive class DRG Class 12, a German steam locomotive class comprising the following eight-coupled, express locomotives operated by the Deutsche Reichsbahn: Class 12.0: BBÖ 214 Class 12.1: BBÖ 114 EAR 12 class, steam locomotive Indian locomotive class WAG-12, electric locomotive JNR Class C12, steam locomotive LSWR A12 class, steam locomotive LSWR L12 class, steam locomotive MGWR Class 12, steam locomotive New South Wales Z12 class locomotive, steam locomotive NSB Class 12, steam locomotive PKP Class Ol12 Queensland A12 class locomotive, steam locomotive Prussian G 12 SNCB Type 12, a Belgian steam locomotive SNCB Class 12, a Belgian electric locomotive Southern Pacific class AC-12, steam locomotive VR Class Dm12, railcar VR Class Dr12, diesel locomotive VR Class Dv12, diesel locomotive
Other ARD-12-class floating dry dock O 12-class submarine Twelfth grade, referred to as "class 12" in India
See also Type 12 (disambiguation)