Nikolaidis (Greek: Νικόλαος Χ. Νικολαΐδης, in French Nicolas Nicolaïdès; (1826 – July 11, 1889) was an author, mechanical engineer, mathematician, soldier, and professor.

His professors in France included Joseph Bertrand and Adhémar Jean Claude Barré de Saint-Venant.

His memoirs, a work of over four hundred pages entitled Analectes, ou Mémoires et Notes sur les Diverses Parties des Mathématiques published in 1874, feature most of his mathematical papers.

He influenced countless French and Greek mathematicians, including Cyparissos Stephanos, John Hazzidakis and Vassilios Lakon.

His professor at the École nationale des ponts et chaussées was mechanician and mathematician Adhémar Jean Claude Barré de Saint-Venant.

He abandoned his teaching position at the École nationale des ponts et chaussées because of his disagreement with Bresse.

In 1863, Nikolaidis published Théorie du Mouvement d'une Figure Plane dans son Plan Application aux Organes des Machines and in 1864 he published his dissertation, Mémoire Sur la Théorie Générale des Surfaces.

Three years later he published an accumulation of his complex mathematical work in French entitled Analectes, ou Mémoires et Notes sur les Diverses Parties des Mathématiques.