Marie Ennemond Camille Jordan (French: [ʒɔʁdɑ̃]; 5 January 1838 – 22 January 1922) was a French mathematician, known both for his foundational work in group theory and for his influential Cours d'analyse.

He was an engineer by profession; later in life he taught at the École polytechnique and the Collège de France, where he had a reputation for eccentric choices of notation.

He is remembered now by name in a number of results: Jordan's work did much to bring Galois theory into the mainstream.

His Traité des substitutions, on permutation groups, was published in 1870; this treatise won for Jordan the 1870 prix Poncelet.

[2] The asteroid 25593 Camillejordan and Institut Camille Jordan [fr] are named in his honour.