Class 21 or 21 Class may refer to: Atlantic 21-class lifeboat Belgian Railways Class 21, Belgian electric locomotive British Rail Class 21 (NBL), British diesel-electric locomotive British Rail Class 21 (MaK), various locomotives used by Eurotunnel GS&WR Class 21 Hormuz 21-class landing ship L&YR Class 21, British 0-4-0ST steam locomotive NSB Class 21, Norwegian 2-6-0 steam locomotive O 21-class submarine P21-class patrol vessel PKP class ET21 South African Class 21 2-10-4, South African steam locomotive
See also Type 21 (disambiguation)