St. Isidore or Saint-Isidore may refer to:

• Isidore of Chios (d. 251), martyr from Roman Egypt
• Isidore of Scété (died c. 390), Egyptian priest and desert ascetic
• Isidore of Pelusium (d. c. 450), monk from Roman Egypt
• Isidore of Seville (c. 560–636), scholar and Archbishop of Seville, Spain
• Isidore the Laborer (c. 1070–1130), peasant and patron saint of Madrid, Spain

• St. Isidore, Alberta
• St. Isidore, Ontario
• St. Isidore-de-Bellevue, Saskatchewan
• Saint-Isidore, New Brunswick
• Saint-Isidore Parish, New Brunswick
• Saint-Isidore, Montérégie, Quebec
• Saint-Isidore-de-Clifton, Quebec
• Saint-Isidore, Chaudière-Appalaches, Quebec

• Church of St. Isidore, Renavas, Lithuania
• St. Isidore Island, Antarctica
• St Isidore's, Queensland, Australia, a homestead
• St. Isidore Cathedral, Holguín, Cuba
• St. Isidore Catholic Church, Los Alamitos, United States
• Saint Isidore Cemetery, Madrid, Spain

• San Isidro (disambiguation)