Castro is a Romance language word that originally derived from Latin castrum, a pre-Roman military camp or fortification (cf: Greek: kastron; Proto-Celtic:*Kassrik; Breton: kaer, *kastro). The English-language equivalent is chester.

It may refer to:

• Castro (surname), a surname (including a list of people with the name)
  • Fidel Castro (1926–2016), leader of Cuba, former First Secretary of the Communist Party of Cuba
  • José Castro (1808–1860), Mexican Californio politician, statesman, and general who served as interim Governor of Alta California and later Governor of Baja California
  • Julián Castro (Venezuelan politician) (1810–1875) a Venezuelan military officer and President of Venezuela between 1858 and 1859
  • Julian Castro (b. 1974), American politician from San Antonio
  • Raúl Castro (b. 1931), younger brother of Fidel Castro, former First Secretary of the Communist Party of Cuba
  • Xiomara Castro (b. 1959), president of Honduras and wife of former Honduran president Manuel Zelaya
• de Castro, a Portuguese surname
• House of Castro, a Spanish noble family
• Prince Carlo, Duke of Castro, claimant to the headship of the royal House of Bourbon-Two Sicilies
• A nickname of Martin Castrogiovanni (born 1981), Argentine-born Italian rugby player
• Castro (Brazilian footballer), the mononym of Luiz Felipe Castro Neto, Brazilian footballer
• Castro (Spanish footballer), the mononym of Santiago Castro Anido, Spanish footballer

• Roman Catholic Diocese of Castro (disambiguation)
• Castro Barros (disambiguation)
• Castro Street (disambiguation)
• Castro City (disambiguation)

• Castro, Paraná, a municipality in the state of Paraná in the Southern Region of Brazil.

• Castro, Chile

• Curiate Italian designation for the Latin Catholic titular bishopric of Moglæna, now Almopia, a municipality of the Pella regional unit in Greek Macedonia.

• Castro, Apulia, a comune (municipality) in the province of Lecce
  • the former Roman Catholic Diocese of Castro di Puglia, now a Latin Catholic titular see
• Castro, Lazio, a destroyed town in the province of Viterbo
  • the former Roman Catholic Diocese of Castro del Lazio, now a Latin Catholic titular see
• Castro, Lombardy, a comune in the province of Bergamo
• Castel di Castro, 13th century fortified city at the site of modern Cagliari, Sardinia
• A former town within the comune of Oschiri, Sardinia
  • the former Roman Catholic Diocese of Castro di Sardegna, now a Latin Catholic titular see

• Castro, Baja California

• Castro (Soria)
• Castros (Spain)
• Castro Caldelas, Galicia
• Castro Urdiales, Cantabria

• Castro, Ticino

• Castro County, Texas
• Castro Cove, an embayment of the San Pablo Bay in Richmond, California
• Castro Creek, a creek in Richmond, California
• Castro Street Station, a Metro station in San Francisco, California
• Castro Theatre, a movie theater in San Francisco, California
• The Castro, San Francisco, a neighborhood in San Francisco, California
• Castro Valley, California, a census-designated place in Alameda County

• Castro culture, Iron-Age, Bronze-Age and Celtic culture in the Northern Iberian Peninsula
  • Castros in Spain
  • Castro (village), types of settlements of the Castro culture
• Castro (clothing), an Israel-based clothing company
• "Castro" (song), a 2016 song by Yo Gotti
• Wars of Castro, conflict between the Papacy and the Farnese dukes of Parma
• Castro FC, Spanish football team
• Jose Castro House, historic Monterey Colonial adobe house built in 1840

• Castor (disambiguation)
• Castrelo de Miño and Castrelo do Val (with the Galician/Portuguese diminutive)
• Castro brothers (disambiguation)
• Castrum
• De castro family (disambiguation)
• Duke of Castro (disambiguation)
• Gastro-, common English-language prefix derived from the ancient Greek γαστήρ gastēr ("stomach")
• Kastro (disambiguation)