Sylvester Krnka (in Czech Sylvestr Krnka; 29 December 1825, Velký Bor – 4 January 1903, Michle) was a Czech gunsmith and inventor, best known for his M1867 Russian Krnka.
At the age of thirteen he entered into the apprenticeship with the well-known gunsmith master Novotny in Vienna later known as company Springer. Some years later he became a burgess of Volyně in the South Bohemian Region where he shortly had his own workshop since 1848. In 1871 he moved to Michle, then a village near Prague, where he opened his gunsmith workshop (which later became a factory). He died in 1903 in Michle. Krnka was the designer of a breechloader rifle, a conversion of the muzzle-loading Model 1857 rifle musket. Although he had been continuously declined by the Austrian military authorities, he was more successful in Montenegro, in Russia – in the Russo-Turkish War (1877–78) his M1867 Russian Krnka triumphed – in Romania, Bulgaria, Sweden and in Norway.
He had been awarded with many decorations and orders in Russia, Montenegro, Sweden and Norway.
His son (1858–1926) carried on with his father's work.