The Terrassa witch trials took place in Terrassa, then in the Principality of Catalonia, Spain between 1615 and 1619. Six women of the city of Terrassa were accused of witchcraft and sentenced to death on 27 October 1619.

During the year preceding the witch trials, the area had suffered a complicated social situation with deep divisions between the rich and poor and many economic problems. The Church had evolved ideologically and no longer considered supernatural phenomena as the work of heretics. Consequently, extreme climatic conditions, such as droughts and frost or the death of animals and children were often attributed to the work of witches.

Spain had relatively few witch trials compared to other areas in Europe, since the Spanish Inquisition had issued mild guidelines in cases of witchcraft after the Navarre witch trials (1525-26), and the Terrassa witch trials took place during the period of the most intense witch panic, in 1618–1622, after which the witch trials in Spain nearly disappeared.

Despite this, many citizens of the town of Terrassa were upset as they believed that they were surrounded by witches. According to local legends, groups of women met with the devil, supposedly dancing frantic dances, losing control of themselves and surrendering themselves to the devil.  Some historians have commented that these meetings of women, if they occurred, could have had a practical component, such as discussion and resolution of domestic problems or health issues. At the time, problems related to sexuality or female health had been marginalised by exclusively male practitioners of 'official' medicine.

In this historical climate, Joana Ferré was accused of witchcraft in Terrassa in 1615 together with ten other women.

On 2 July 1615, the Holy Office of Barcelona asked the local authorities to transfer the accused women to the Catalan capital. Out of the 11 accused women, only three were incarcerated: Margarida Cotilla, Micaela Casanovas (known as Esclopera) and Guillermina Font (known as Miramunda). The others were released to return to Terrassa or flee to other cities. Those that returned to Terrassa continued to be suspected of witchcraft and were persecuted, publicly stoned or accused of prostitution.

Given the climate of hysteria in the town, on 26 December 1618, the officials of the town of Terrassa invited the Witch Hunter Joan Font from Sellent, agreeing to pay his expenses from the public purse. With his help, they formed a civil tribunal on 23 May 1619 that consisted of the Mayor and his advisors. They detained and condemned six women, some of which had already been released by the Inquisition a few years before. Their names were Margarida Cotilla, Joana de Toy, Joana Sabina, Micaela Casanovas, Eulàlia Totxa and Guillermina Font (known as Miramunda).

The accusations against the women were surprising. In one, Margarida Tafanera was accused by her own brother of bewitching his wife so that they couldn't have children and so she, Margarida, would inherit all his assets. In another, a neighbour, Antoni Ubres, stated that the women met on Thursday nights in an area called "la cuadra d’en Palet" where they waited for the devil, who appeared in a chair wearing a red. When he appeared, the neighbour said that the women kissed his hand. After the devil served a sinister dinner, he played the flute and fell into a scandalous orgy with the women.