Nimzowitsch (Nimtsovich) Aron Isaevich (07 November 1886, Riga — 16 March 1935, Copenhagen) — chess player, chess theorist, and writer.

Aron Nimzowitsch was a student of Kārlis Bētiņš. From 1902 he studied at the universities of Berlin, Heidelberg, and Zurich. He made his international debut in Coburg in 1904. His first major success came at the Munich tournament in 1906, where he took first place and earned the title of chess master.

In 1918 he moved to Sweden, and in 1923 to Denmark. He was a winner and prize-winner in many international tournaments, including Marienbad (Mariánské Lázně, 1925, shared 1st–2nd place), Dresden (1926, 1st place), London (1927, 1st place), Berlin (1928, 1st place), and Karlovy Vary (1929, 1st place).

He was recognized by the chess world as a challenger for the world championship, but was unable to raise the required prize fund of 10,000 US dollars.

In 1925 he published his fundamental chess works Chess Blockade and My System, followed in 1929 by My System in Practice. He was also the author of numerous articles in periodicals. Nimzowitsch made a major contribution to the development of opening theory; the most famous are the Nimzowitsch Defense and the Nimzowitsch Opening.