The Siedlec Desert (Polish: Pustynia Siedlecka) is an area of sand near the village of Siedlec, district of Gmina Janów, within Częstochowa County, Silesian Voivodeship, in the Kraków-Częstochowa Upland area of southern Poland.

The "desert" was formed during sand-mining operations, with the sand itself coming from a buried Jurassic period seabed.

The dunes at Siedlec reach up to 30 meters high and mirages are visible there in summer.

Local legend has it that the desert was formed when a clever sorcerer pursued by the Devil escaped through the gates of hell, leaving the area around scorched.

[1] The desert forms part of the Olsztyńsko-Gorzkowskie micro-region, and the dunes within it are the result of Aeolian processes.