The Loudun possessions, also known as the Loudun possessed affair, was a notorious witchcraft trial that took place in Loudun, Kingdom of France, in 1634. A convent of Ursuline nuns said they had been visited and possessed by demons. Following an investigation by the Catholic Church, a local priest named Urbain Grandier was accused of summoning the evil spirits. He was eventually convicted of the crimes of sorcery and burned at the stake.

Loudun is a commune in the Vienne department and the region of Nouvelle-Aquitaine, western France.