The Cult of the Supreme Being (French: Culte de l'tre suprme) was a form of deism established in France by Maximilien Robespierre during the French Revolution. It was intended to become the state religion of the new French Republic and a replacement for Roman Catholicism and its rival, the Cult of Reason. It went unsupported after the fall of Robespierre and was officially proscribed by First Consul Napoleon Bonaparte in 1802.

Maximilien François Marie Isidore de Robespierre (French: [mak.si.mi.ljɛ̃ ʁɔ.bɛs.pjɛʁ]; 6 May 1758 – 28 July 1794) was a French lawyer and statesman who became one of the best-known and most influential figures of the French Revolution. As a member of the Constituent Assembly and the Jacobin Club, he campaigned for universal manhood suffrage and the abolition both of celibacy for the clergy, and slavery. In 1791, Robespierre was elected as "public accuser" and became an outspoken advocate for male citizens without a political voice, for their unrestricted admission to the National Guard, to public offices, for the right to petition and the right to bear arms in self defence. Robespierre played an important part in the agitation which brought about the fall of the French monarchy on 10 August 1792 and the summoning of a National Convention. His goal was to create a one and indivisible France, equality before the law, to abolish prerogatives and to defend the principles of direct democracy.As one of the leading members of the Paris Commune, Robespierre was elected as a deputy to the French Convention in early September 1792 but was soon criticised for trying to establish either a triumvirate or a dictatorship. In April 1793, Robespierre urged the creation of a sans-culotte army to enforce revolutionary laws and sweep away any counter-revolutionary conspirator, leading to the armed Insurrection of 31 May – 2 June 1793. Because of his health, Robespierre announced he was to resign but in July he was appointed as a member of the powerful Committee of Public Safety, and reorganized the Revolutionary Tribunal. In October, after Robespierre proposed in vain to close the convention, the Committees declared themself a revolutionary government, the joint domination of the Committee of Public Safety and Committee of General Security. Those who were not actively defending France (modérantisme) became his enemy. He exerted his influence to suppress the republican Girondins to the right, the radical Hébertists to the left and then the indulgent Dantonists in the centre.

Robespierre is best known for his role as a member of the Committee of Public Safety as he signed 542 arrests, especially in the spring and summer of 1794. The question of just how personally responsible Robespierre was for the law of 22 Prairial remains controversial, but it is clear he did not accept any changes. Coming into effect at the height of the la Grande Terreur, the law removed the few procedural guarantees still afforded to the accused, vastly expanded the power of the tribunal, and ultimately resulted in the number of executions in France rising dramatically. Although Robespierre always had like-minded allies, the politically motivated bloodshed that he incited disillusioned many. Moreover, the deist Cult of the Supreme Being that he had founded and zealously promoted generated suspicion in the eyes of both anticlericals and other political factions, who felt he was developing grandiose delusions about his place in French society.Robespierre was eventually undone by his obsession with the vision of an ideal republic and his indifference to the human costs of installing it, turning both members of the Convention and the French public against him. The Terror ended when he and his allies were arrested in the Paris town hall on 9 Thermidor. Robespierre was wounded in his jaw, but it is not known if it was self-inflicted or the outcome of the skirmish. About 90 people, including Robespierre, were executed in the days after, events that initiated a period known as the Thermidorian Reaction.A divisive figure during his lifetime, Robespierre remains controversial to this day. His legacy and reputation continue to be subject to ongoing academic and popular debate. To some, Robespierre was the Revolution's principal ideologist and embodied the country's first democratic experience, marked by the often revised and never implemented French Constitution of 1793. To others, he was the incarnation of the Terror itself, and provided in his speeches a justification of civilian armament. British historian George Rudé estimates that Robespierre made some 900 speeches, in which he often expressed his political and philosophical views forcefully.