KM, Km, or km may stand for:

• Knight of the Sovereign Military Order of Malta, a chivalric order

• KM Group, a multimedia group based in Kent
• Kennis Music, a record label
• Kia Motors, an automobile manufacturer
• Kmart (former stock symbol "KM")
• Konica Minolta, a manufacturer of electronics
• KM Malta Airlines, the flag carrier of Malta

• Knight of Malta (disambiguation), a Christian order of knighthood
• Kaiserliche Marine, navy of the German Empire
• Kriegsmarine, name of the German navy during the Nazi regime
• Koninklijke Marine, Dutch name of the Royal Netherlands Navy

• Kamenz (district), Germany (license plate indication)
• Messenia, Greece (license plate indication)
• KM Junction, West Virginia
• Comoros, country (ISO 3166-1 code KM)
• Kysucké Nové Mesto, town in Slovakia (district code KM)
• Kosovska Mitrovica, town in Serbia
• Kosovo and Metohija, an autonomous province in Serbia (ISO 3166-2 code RS-KM)

• Kilometre (km), SI unit of distance
• .km, Internet top-level domain (ccTLD) for Comoros
• Km, an electric motor constant
• Kaplan–Meier estimator, a non-parametric statistic used to estimate the survival function
• Kelley–Morse set theory, in mathematics, a set theory
• Kernel methods, a set of computer science algorithms
• K_M, the Michaelis constant in Michaelis–Menten kinetics
• Knowledge management, a range of techniques to identify, represent, and distribute knowledge

• Kevin Matthews (wrestler), Kevin Matthew McDonald (b. 1983)
• KM (rapper), Syed Omar Kashaff (b. 2002)
• Km (hieroglyph)
• KM-mount, a Konica camera rangefinder mount
• Khmer language (ISO 639 alpha-2 code "km")
• KM, a Soviet ground-effect vehicle, nicknamed the "Caspian Sea Monster"
• Bosnia and Herzegovina convertible mark, currency of Bosnia and Herzegovina
• Krause-Mishler numbers for the Standard Catalog of World Coins