Zeleznik may refer to:
People Lukáš Železník (born 1990), Czech footballer Martin Železník (born 1989), Slovak footballer
Places Železnik, Serbia FK Železnik, a football club Železník (village), Slovakia Żeleźnik, Poland Demir Hisar (region), also known as Železnik, a region in North Macedonia
Other uses Železník (horse) (1978–2004), Czechoslovak racehorse