K class or Class K may refer to:
Railways Commonwealth Railways K class, Australia LB&SCR K class (1913), England SECR K and SR K1 classes (1914), England Metropolitan Railway K Class, England NBR K Class, Scotland NZR K class (1877), New Zealand NZR K class (1932), New Zealand South Australian Railways K class (broad gauge), South Australia South Australian Railways K class (narrow gauge), South Australia Tasmanian Government Railways K class, Tasmania Victorian Railways K class, Australia WAGR K class, steam, Western Australia WAGR K class (1891), steam, Western Australia WAGR K class (diesel), Western Australia K-class Melbourne tram K-class Sydney tram
Ships K-class destroyer, British warships of World War II German K class cruiser, German warships of World War II K-class sloop, Dutch warships K-class submarine (disambiguation), several classes of warships British Columbia K-class ferry, Canadian ships Sydney K-class ferry, Sydney Harbour ferries K-class torpedo boat, Dutch warships
Other uses K-class blimp, blimps built for the US Navy Class K, a classification for stars Energy class, an earthquake magnitude scale