K21 (disambiguation)

K21 is a South Korean infantry fighting vehicle.

K21 may also refer to:

Automobiles

• Changhe Freedom K21, a Chinese pickup truck

Ships

• HMS Dart (K21), a frigate of the Royal Navy
• HSwMS Göteborg (K21), a corvette of the Swedish Navy
• Soviet submarine K-21

Aircraft

• Schleicher ASK 21, a two-seater training glider commonly referred to as the K21

• Gastroesophageal reflux
• Lactobacillus plantarum strain K21
• Uniform k₂₁ polytope
• "Va, dal furor portata", an aria by Wolfgang Amadeus Mozart