A sierra is a word from the Spanish language meaning a mountain range (serra in Portuguese and Latin). It is used for various mountains and mountain ranges in Spanish- and Portuguese-speaking countries.

Sierra mountains or Sierra Mountain may refer to any one of the following:

Mountain ranges

• In Argentina:
  • Sierra de Córdoba, in the central region of the country

• In Brazil:
  • Serra do Mar, in the country's southeast

• In Mexico:
  • Sierra Juárez, in Baja California
  • Sierra Madre del Sur, in the country's south
  • Sierra Madre Occidental, in the northwest of the country
  • Sierra Madre Oriental, in the northeast of the country
  • Sierra Nevada (Mexico), running across the central portion of the country
  • Sierra San Pedro Mártir, in Baja California

• In the Philippines:
  • Sierra Madre (Philippines), on the island of Luzon

• In Portugal:
  • Serra da Estrela, in the north central region of the country
  • Serra de Montejunto, in the west region of the country
  • Serra da Vila, in the west region of the country
  • Serra do Socorro, in the west region of the country

• In Spain:
  • Sierra de Gata, in the west of the country
  • Sierra de Gredos, near the central region of the country
  • Sierra de Guadarrama, in the central part of the country
  • Sierra de Mijas, in the south of the country
  • Sierra Morena, in the county's south
  • Sierra Nevada (Spain), in the southeast of the country

• In the United States:
  • Sierra Ancha in central Arizona
  • Sierra Blanca, in New Mexico
  • Sierra Estrella, in southwestern Arizona
  • Sierra Madre Mountains (California), in southwestern California
  • Sierra Nevada (U.S.), also known as The Sierras and located in California and Nevada

• In the Uruguay:
  • sierra de Minas in the central part of the country
  • Sierra de Carapé in the central part of the country

Single mountains

• Antofagasta de la Sierra in Argentina
• Sierra Negra in Puebla, Mexico
• Sierra Negra (Galápagos), in Galápagos Province, Ecuador
• Sierra Nevada (stratovolcano), in Chile
• Sierra Nevada de Lagunas Bravas, on the border of Argentina and Chile
• Sierra Nevada de Santa Marta, in Colombia