Nikolai Dimitrovich Avksentiev (Russian: Николай Дмитриевич Авксентьев; 1878, Penza – 1943, New York City) was a leading member of the Russian Socialist-Revolutionary Party (PSR). He was one of the 'Heidelberg SRs' (a group of Russian students at the University of Heidelberg in the 1890s), like V.M. Zenzinov. These SRs were influenced by Neo-Kantian philosophy and Marxism.
During the First World War Avksentiev was associated with the 'Defencist' wing of the PSR and collaborated closely with V.V. Rudnev, A.R. Gots and others. He was an active member of the irregular freemasonic lodge, the Grand Orient of Russia’s Peoples. He supported the February Revolution of 1917 and held various positions in the Duma, the Soviet and the Provisional Government under A.F. Kerensky, including succeeding Georgy Lvov as Minister of the Interior, 15 March 1917 – 21 July 1917. Avksentiev opposed the Bolshevik October Revolution and was briefly arrested by the Bolsheviks. In November 1918 he participated in the anti-Bolshevik 'Directorate' at Omsk but soon fell out with the military counter-revolutionaries around Admiral Kolchak.
Briefly arrested by Kolchak, Avksentiev fled Russia via Vladivostok, with the assistance of the British military. He settled in Paris and was active in émigré circles and in Freemasonry. After the German invasion of France in 1940, Avksentiev and his wife Berthe escaped to America with an emergency visa provided by the Jewish Labor Committee and the American Federation of Labor.