Witold Pilecki (; 13 May 190125 May 1948), known by the codenames Roman Jezierski, Tomasz Serafinski, Druh and Witold, was a Polish World War II cavalry officer, intelligence agent, and resistance leader.

As a youth, Pilecki joined Polish underground scouting; in the aftermath of World War I, he joined the Polish militia and, later, the Polish Army.