K3

Transportation

• K-3 (Kansas highway), a state highway in Kansas
• London Buses route K3
• K3, IATA code for Alaskan commuter airline Taquan Air
• K-3 cart

Vehicles

• LNER Class K3, a steam locomotive
• GSWRI Class K3, a Great Southern and Western Railway (Ireland) steam locomotive

Military

Units

• Livregementets husarer, Swedish cavalry regiment

Weapons

• K-3 (rifle), an Armenian-made bullpup rifle
• Daewoo K3, a light machine gun

Ships

• Soviet submarine K-3 Leninsky Komsomol, the first Soviet nuclear submarine
• USS K-3 (SS-34), a 1914 United States Navy K-class submarine
• HMS K3, a 1916 British K class submarine
• HMS Heliotrope (K03), a 1940 British Navy Flower class corvette

Airfields

• United States Air Force designator for Pohang Airport during the Korean War

Science, technology, computing and mathematics

• K3, the third version of the k programming language created by Arthur Whitney
• K3 surface, a compact complex surface in mathematics
• K₃, vitamin, Menadione
• K3, 1774 marine chronomoter made by Larcum Kendall

Media and entertainment

• K3 (band), a Belgian/Dutch girl group
• K3 (television), a Catalan television channel
• K3: Prison of Hell, a 2009 pornographic horror film

Other

• K3 League, a Korean football league
• Broad Peak, a mountain previously called K3
• Kankakee, Illinois, an expression or abbreviation used to identify Kankakee, IL