Achille Ernest Oscar Joseph Delesse (3 February 1817 – 24 March 1881) was a French geologist and mineralogist. He was born at Metz. At the age of twenty he entered the École Polytechnique, and subsequently passed through the Ecole des Mines. In 1845, he was appointed to the chair of mineralogy and geology at Besançon; in 1850, to the chair of geology at the Sorbonne in Paris; and in 1864, professor of agriculture at the Ecole des Mines. He was elected as a member to the American Philosophical Society in 1863. In 1878, he became inspector-general of mines. He died in Paris on 24 March 1881.