Ignacy Domeyko (also spelt Domejko) (b. July 3, 1802 in Niedźwiadka - January 13, 1889 in Santiago de Chile) was a Polish geologist and mineralogist.

He studied at the Vilnius University and the Ecole des Mines in Paris. Ignacy was a close friend of the writer Adam Mickiewicz. After being involved in the November Uprising in 1831, he chose to emigrate instead of facing Russian reprisals. In 1838 he left for Chile, where he lived until his death.

He was a professor of a mining college at Coquimbo and later (1867-1883) president of the University of Santiago de Chile.

He greatly developed studies in mineralogy and mining techniques, researched several new minerals, and was also a meteorologist and ethnographer.

pl:Ignacy Domeyko