P class or Class P may refer to:

• P (complexity), a computational complexity class

• Two classes of steam locomotives used by the New Zealand Railways Department:
  • NZR P class (1876), of 1876
  • NZR P class (1885), of 1885
• WAGR P Class, a 1924 express steam-locomotive of the Western Australian Government Railways
• V/Line P class, a type of diesel electric locomotive, in service with V/Line and Pacific National in Australia
• SECR P class, a class of locomotives of the South Eastern and Chatham Railway in the UK
• DSB class P, a class of steam locomotives of the Danish State Railways
• NER Class P, a class of steam locomotives of the North Eastern Railway
• Palestine Railways P class
• P-class Melbourne tram
• P-class Sydney tram

• P-class cruiser, a class of 12 heavy cruisers planned for construction by the Kriegsmarine during the late 1930s, but cancelled before any could be built
• Pelorus-class cruiser, a class of 11 protected cruisers operated by the Royal Navy and Royal Australian Navy from the 1890s to the 1920s
• P-class destroyer, a class of 8 Royal Navy destroyers built during World War II
• P-class sloop, operated by the British navy during World War I
• P-class submarine (disambiguation), a number of submarine classes
• P-class sailing dinghy, a New Zealand sailing dinghy design first created in the 1920s, popularly used for sail training
• P-class yacht (Universal Rule), a development class for America's Cup racing yachts under the Universal Rule

This disambiguation page lists articles associated with the title P class.
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