Ernest Granger (20 April 1844 – 21 May 1914) was a French politician, a veteran of the Paris Commune of 1871, a Blanquist socialist and subsequently a Boulangist nationalist.

Around this time he became involved in the clandestine revolutionary societies organised by the followers of the incarcerated veteran insurrectionist Louis-Auguste Blanqui.

On August 14, 1870, the Blanquists struck, attempting to seize a military arsenal and spark a general uprising; Granger was one of the organisers.

The Blanquists launched a campaign for the release of their aged and infirm leader, and in 1879, they managed to have Blanqui elected to the National Assembly as deputy for Bordeaux.

Shortly after Blanqui's death, Granger, together with Édouard Vaillant and others, founded the Central Revolutionary Committee, the nucleus of the Blanquist party.

However, the Blanquist ideology at this time was an unstable combination of radical Jacobin republicanism, egalitarian socialism, anti-clericalism, ardent national chauvinism and a strong current of xenophobia and antisemitism.

One faction of the Blanquist movement accented the socialist heritage of Blanqui and moved closer to Jules Guesde's Marxist party, rejecting antisemitism and, at least in theory, endorsing the internationalist principles of socialism.

Although his was the smaller faction, Granger, who had been personally close to Blanqui, considered himself the true standard bearer of Blanquism, and Vaillant a late interloper.

They feared that Boulanger was preparing a coup d'état and intended to replace the Republic with his personal dictatorship, and they were alarmed by his financial and political ties to Orléanist monarchists.

Rochefort was a veteran republican with socialist sympathies and personal ties to many Blanquists and ex-Communards, but in the 1880s he had become a supporter of Boulanger and was running as a Boulangist candidate.

The majority of French socialists followed Jean Jaurès in supporting Alfred Dreyfus, the Jewish officer falsely accused of spying for Germany, or at least maintained a policy of neutrality between the "bourgeois" Dreyfusards and anti-Dreyfusards (as Vaillant and Guesde did).