Jan Piwnik (31 August 1912 – 16 June 1944) was a Polish World War II soldier, a cichociemny and a notable leader of the Home Army in the Świętokrzyskie Mountains.

He joined the Polish Army, reconstituted in France at that time and was assigned to the 4th Rifle Brigade (en cadre).

After evacuation to Great Britain following the fall of France, he joined the Polish 1st Independent Parachute Brigade under General Stanisław Sosabowski.

In the summer of 1942, he was assigned to head one of the Wachlarz units operating from Równe in eastern Poland (now Rivne in western Ukraine).

For his action, he was promoted to ensign and in March was assigned to the Radom-Kielce Home Army Area as the commanding officer of all Kedyw forces there.

After the start of the Operation Tempest, his unit was reformed into the VII battalion of the 77th Home Army Infantry Regiment and took part in many successful actions behind German lines.