Louis Auguste Blanqui (February 8, 1805 - January 1, 1881) was a French political activist.

He was born in Puget-Théniers , Alpes-Maritimes, where his father, Jean Dominique Blanqui, was subprefect. He studied both law and medicine, but found his real vocation in politics, and quickly became a champion of the most advanced opinions. He took an active part in the July Revolution of 1830, and for maintaining the doctrine of republicanism during the reign of Louis Philippe, was condemned to repeated terms of imprisonment. Implicated in the armed outbreak of the Société des Saisons, of which he was a leading spirit, he was in 1840 condemned to death, a sentence later commuted to life imprisonment.

He was released during the revolution of 1848, only to resume his attacks on existing institutions. The revolution did not satisfy him. The violence of the Société républicaine centrale, which was founded by Blanqui to demand a modification of the government, brought him into conflict with the more moderate Republicans, and in 1849 he was sentenced to ten years' imprisonment.

In 1865, while serving a further term of imprisonment under the Empire, he escaped, and continued his propaganda campaign against the government from abroad, until the general amnesty of 1869 enabled him to return to France. Blanqui's leaning towards violence was illustrated in 1870 by two unsuccessful armed demonstrations: one on January 12 at the funeral of Victor Noir, the journalist shot by Pierre Bonaparte; the other on August 14, when he led an attempt to seize some guns at a barrack. Upon the fall of the Empire, through the revolution of September 4, Blanqui established the club and journal La patrie en danger.

He was one of the group that briefly seized the reins of power on October 31, and for his share in that outbreak he was again condemned to death on March 17 of the following year. A few days afterwards the insurrection which established the Paris Commune broke out, and Blanqui was elected a member of the insurgent government, but his detention in prison prevented him from taking an active part. Nevertheless he was in 1872 condemned along with the other members of the Commune to transportation; on account of his broken health this sentence was commuted to one of imprisonment. In 1879 he was elected a deputy for Bordeaux; although the election was pronounced invalid, Blanqui was freed, and immediately resumed his work of agitation.

After a speech at a revolutionary meeting in Paris, he was struck down by apoplexy. He died on January 1, 1881 and was interred in the Père Lachaise Cemetery.

His uncompromising communism, and his determination to enforce it by violence, had brought him into conflict with every French government, and half his life had been spent in prison. Besides his innumerable contributions to journalism, he published an astronomical work entitled L'Eternité par les astres (1872), and after his death his writings on economic and social questions were collected under the title of Critique sociale (1885).