Krzemionki, also Krzemionki Opatowskie ([kʂɛˈmʲjɔnkʲi ɔpaˈtɔfskʲɛ], "Opatów silica-mine"), is a Neolithic and early Bronze Age complex of flint mines for the extraction of Upper Jurassic (Oxfordian) banded flints located about eight kilometers north-east of the Polish city of Ostrowiec Świętokrzyski.

It is one of the largest known complexes of prehistoric flint mines in Europe together with Grime's Graves in England and Spiennes in Belgium.

The Globular Amphora Culture also used the pits and even more intensely, enlarging the area of axehead distribution to about 500 km.

On 6 July 2019, the Krzemionki Prehistoric Striped Flint Mining Region was inscribed as a UNESCO World Heritage Site.

Some of the shafts are connected by short horizontal passage for the purposes of access or drainage called adits.

[3] After the Second World War, the head of the scientific team was Tadeusz Żurowski who explored the mines in Krzemionki, especially in 1958 - 1961.