Pilar Defilló Amiguet (November 11, 1853 - March 11, 1931) was a Puerto Rican musician with Catalan origin, known as the mother of Enric and Pau Casals Defilló.
Daughter of Joseph Defilló Tusquellas (c.1815 - Mayagüez, 1859) and Raimunda Amiguet Ferrer, she emigrated with her mother to El Vendrell, Tarragona, in 1871, where she married Carles Casals Ribes after having been an outstanding pupil of his. Her father had belonged to the Secret Abolitionist Society run by Ramón Emeterio Betances, a friend of the family's.
On May 8, 2015, the birthplace of Pilar Defilló at 21 Calle Mendez Vigo in Mayaguez, Puerto Rico, which had been built in 1841 and recently had been restored, opened as the Casa Museo Pilar Defilló, a cultural museum devoted to Pau Casals.