Karol Pniak (26 January 1910 – 10 November 1980) was a Polish World War II flying ace of the Battle of Britain.

Originally a pilot for the Polish Air Force in the September Campaign of 1939, he later flew with No.

32 Squadron of the Royal Air Force, during the Battle of Britain, where he was known by the nickname "Cognac.

Pilot Officer Pniak then served with 257 Squadron, and was involved in the dogfight with Regia Aeronautica aircraft on 11 November 1940.

He attacked one Fiat BR.20M bomber that began to smoke and burn and then turned onto its back before it dived into the North Sea 10 miles east of Harwich after one man had baled out.