Inessa Fyodorovna Armand (born Elisabeth-Inès Stéphane d'Herbenville; 8 May 1874 – 24 September 1920) was a French-Russian communist politician, member of the Bolsheviks and a feminist who spent most of her life in Russia.

Armand, being an important figure in the pre-Revolution Russian communist movement and the early days of the communist era, had been almost forgotten for some time, until the partial opening of Soviet archives during the 1990s (despite this, many valuable sources regarding her life still remain inaccessible in Russian archives). Historian Michael Pearson wrote about her: "She was to help him (Lenin) recover his position and hone his Bolsheviks into a force that would acquire more power than the tsar, and would herself by 1919 become the most powerful woman in Moscow."

Armand was born in Paris. Her mother, Nathalie Wild, was a comedienne of half-French and half-English descent, and her father, Théodore Pécheux d'Herbenville, was a French opera-singer. Her father died when she was five and she was brought up by her aunt and grandmother living in Moscow, both teachers.

At the age of nineteen she married Alexander Armand, the son of a wealthy Russian textile manufacturer. The marriage produced four children. Inessa and her husband opened a school for peasant children outside of Moscow. She also joined a charitable group dedicated to helping the city's destitute women.

In 1902, she left her husband, with whom she had an open marriage, to marry his younger brother Vladimir, who shared her radical political views, and bore him her fifth child, Andrei.

In 1903, she joined the illegal Russian Social Democratic Labour Party. Armand distributed illegal propaganda; after her arrest in June 1907 she was sentenced to two years' internal exile in Mezen in Northern Russia.

In November 1908 Armand managed to escape from Mezen and eventually left Russia to settle in Paris, where she met Vladimir Lenin and other Bolsheviks living in foreign exile. In 1911 Armand became secretary for the Committee of Foreign Organisations established to coordinate all Bolshevik groups in Western Europe.

Armand returned to Russia in July 1912. This was a risky mission. Lenin needed her to pass on the resolution of the Prague Conference, to help organise the Bolshevik campaign to get its supporters elected to the Duma, and find out what was going on in Pravda. Helen Rappaport notes that Lenin knew her entry into Russia would invite immediate arrest, yet he made light of it, his concerns for party works overcoming his personal feelings for her. Two months later she was arrested and imprisoned, only to be released against bail in March 1913, thanks to Alexander's generous support. Once again illegally leaving Russia, she went to live with Vladimir Lenin and Nadezhda Krupskaya in Galicia. She also began work editing Rabotnitsa. Krupskaya, with admiration, noted that exhausted as Armand was, she threw herself immediately into the party works. Lenin wrote to her and trusted her more than anyone else in his circles. The Okhrana considered Armand to be the right hand of Lenin. According to author Ralph Carter Elwood, "Even more than Trotsky during the Iskra period, she became Lenin’s ‘cudgel’ — someone to beat wavering Bolsheviks back into line, to convey uncompromising messages to his political opponents, to carry out uncomfortable missions which Lenin himself preferred to avoid".