K56

K56 or K-56 may refer to:


 * K-56 (1927–1937 Kansas highway), an historical designation of Kansas state highway K-52
 * K-56 (1937–1957 Kansas highway), an historical designation of Kansas state highway K-98
 * HMS Asphodel (K56), a British Royal Navy Flower-class corvette
 * Potassium-56 (K-56 or 56K), an isotope of potassium
 * Soviet submarine K-56, various submarines of the Soviet Navy