M class or M-class may refer to:
Military M-class blimp, an American WW2 class of anti-submarine warfare airships M-class cruiser, a planned German light cruiser class M-class destroyer, several classes of destroyer Admiralty M-class destroyer, a class of British destroyers built 1913–1916 and served in World War I M-class, British destroyers starting with the letter M of the L and M-class destroyer, launched 1939–1942 and served in World War II Marcílio Dias-class destroyer, Brazilian destroyers built during World War II Karel Doorman-class frigate, of the Royal Netherlands Navy M-class minesweeper, several classes of minesweeper M-class minesweeper (Germany), a class of minesweepers of the World War II German Kriegsmarine M-class minesweeper (Netherlands), a class of minesweepers of the Royal Netherlands Navy built after World War I Abercrombie-class monitor, a British WWI class of monitor gunships M-class submarine, several classes of submarine British M-class submarine United States M-class submarine
Transportation Mercedes-Benz M-Class, an automobile M-segment, a European vehicle size class NBR M Class 4-4-0, steam locomotives NZR M class locomotives Pennsylvania Railroad class M1, locomotives South Australian Railways M class (first), 0-4-2 steam locomotives South Australian Railways M class (second), 2-4-2T steam locomotives Tasmanian Government Railways M class (1912), 4-4-2+2-4-4 steam locomotives Tasmanian Government Railways M class (1952), 4-6-2 steam locomotives Victorian Railways M class, steam locomotives Victorian Railways M class (diesel-hydraulic), shunting locomotives WAGR M class, 2-6-0+0-6-2 steam locomotives WAGR M class (1875), 2-6-0 steam locomotives WAGR M class (diesel), diesel-hydraulic locomotives OOCL M-class container ship, a class of large container ships operated by Orient Overseas Container Line Maersk M-class container ship, a class of large container ships operated by Maersk Line M-class Melbourne tram M-class Sydney tram
Astronomy M class, a stellar classification M class, a class of solar flare
See also Class M (disambiguation) M type (disambiguation)