The Great Fear (French: Grande Peur) was a general panic that took place between 22 July to 6 August 1789, at the start of the French Revolution. Rural unrest had been present in France since the worsening grain shortage of the spring. Fuelled by rumours of an aristocrats' "famine plot" to starve or burn out the population, both peasants and townspeople mobilised in many regions.

In response to those rumors, fearful peasants armed themselves in self defense and, in some areas, attacked manor houses. The content of the rumors varied. In some areas it was believed that a foreign force was burning the crops in the fields, and in other areas it was believed that robbers were burning buildings. Fear of the peasant revolt was a contributing factor to the abolition of seigneurialism in France through the August Decrees.

French historian Georges Lefebvre has demonstrated that the revolt in the countryside can be followed in remarkable detail. The revolt had both economic and political causes, predating the events of the summer of 1789. As Lefebvre comments, "To get the peasant to rise and revolt, there was no need of the French Revolution, as so many historians have suggested: when the panic came he was already up and away".

The rural unrest can be traced back to the spring of 1788, when a drought threatened the prospect of the coming harvest. Harvests had already been poor since the massive 1783 Laki eruption in Iceland. Storms and floods also destroyed much of the harvest during the summer, leading to both a decrease in seigneurial dues and defaults on leases. Frosts and snow damaged vines and ruined chestnut and olive groves in the south. Vagrancy became a serious problem in the countryside, and in some areas, such as the Franche-Comté in late 1788, peasants gathered to take collective action against the seigneurs. Historian Mary Kilbourne Matossian argues that one of the causes of the Great Fear was consumption of ergot, a hallucinogenic fungus. In years of good harvests, rye that was contaminated with ergot was discarded, but when the harvest was poor, the peasants could not afford to be so choosy.

A recent quantitative study employed epidemiological models to analyze the spatio-temporal spread of rumors during the Great Fear of 1789. This analysis revealed the key transmission parameters and the institutional, demographic, and socio-economic factors of the time (literacy, population size, political participation, wheat prices, income and ownership laws, and the unequal distribution of land ownership) that influenced its diffusion in rural France.

The panic began in the Franche-Comté, spread south along the Rhône valley to Provence, east towards the Alps and west towards the centre of France. Almost simultaneously, a panic began in Ruffec, south of Poitiers, and spread to the Pyrenees, toward Berry and into the Auvergne. The uprising coalesced into a general Great Fear, as neighbouring villages mistook armed peasants for brigands.

During the attacks by the peasants on the estates of the feudal nobility and convent estates, their main objective was reported to have been finding and destroying the documents that granted the lords their feudal privileges over the peasantry, and burn them. In some cases, the manor houses were burned along with the documents. Hundreds of manor houses are reported to have been burned this way, however the houses burnt belonged to the minority of those attacked, and there was no indiscriminate pillaging. In most cases, the peasants simply left when the letters of feudal privileges had been destroyed, rather than burning the house. The members of the aristocracy normally fled from their castles and were rarely subjected to violence, being located by the militia who were sent to reinstate order after the end of the uprising. Of those aristocrats captured by the peasants, most were forced to leave their estates; a minority were reported to have been subjected to mistreatment such as beatings and humiliation; in three instances landlords were killed.

Although the Great Fear is usually associated with the peasantry, all of the uprisings tended to involve all sectors of the local community, including some elite participants, such as artisans or well-to-do farmers. Often the bourgeoisie had just as much to gain from the destruction of the feudal regime as the poorer peasantry.