KB, kB or kb may stand for:

• KB Kookmin Bank, South Korea
• Kaupthing Bank, Iceland
• Komerční banka, Czech Republic
• Kasikornbank, Thailand
• Karafarin Bank, Iran

• National Library of Sweden (Swedish: Kungliga biblioteket)
• National Library of the Netherlands (Dutch: Koninklijke Bibliotheek)

• Kalix BF, a Swedish bandy club
• Kjøbenhavns Boldklub, a sports club, Copenhagen, Denmark

• KB Home, a US house builder
• KB Lager, Australia
• KB Toys, US
• K&B, a New Orleans, Louisiana, US drugstore
• Druk Air (IATA code: KB), Bhutan airline

• Kick Buttowski, an American animated series and titular character

• Kevin Bartlett (Australian rules footballer) (born 1947)
• KB (rapper) (born 1988), Kevin Elijah Burgess
• KB Killa Beats (born 1983), Zambian record producer
• Kobe Bryant (1978–2020), American basketball player
• Kyle Busch (born 1985), American stock car driver

• Kilo-base pair (kb or kbp), length of D/RNA molecule

• Kilobit (kb), 1,000 bits
• Kilobyte (kB), 1,000 bytes
• Knowledge base
  • Microsoft Knowledge Base ID prefix

• KB series, International Harvester trucks
• Isuzu Faster or KB, a pickup truck
  • Isuzu D-Max or KB, a pickup truck
• NZR K^B class, a New Zealand steam locomotive

• Boltzmann constant, k or k_B
• Base dissociation constant K_b
• Ebullioscopic constant K_b, relating molality to boiling point elevation
• Kauri-butanol value Kb, a measure of solvent performance

• King's Buildings, a University of Edinburgh campus
• Knowledge Bowl, a quiz competition
• Former Knight Companion of the Order of the Bath
• Kuala Belait, a town in Brunei
• Kota Bharu, a city in Kelantan, Malaysia
• WWKB, or KB Radio 1520
• A slang name for marijuana