Universidad de San Carlos may refer to:

• University of San Carlos, in Cebu, Philippines
• Universidade Federal de São Carlos, in São Carlos, Brazil
• University of San Carlos of Guatemala, based in Guatemala City
• Universad de San Carlos (Guatemalan football club), based in Guatemala City and commonly known as USAC
• Universidad San Carlos (Paraguay), based in Asunción, Paraguay.

• Adonias Filho
• Adonic feast
• Adonidia
• Adonidia merrillii
• Adonijah Strong Welch
• Adonijah S. Welch
• Adonijah Welch
• Adoni Maropis
• Adoniram Gordon
• Adoniram Holmes
• Adoniram J. Holmes
• Adoniram Judson Gordon
• Adoniram Judson Holmes
• Adoniram J. Warner
• Adoniram Warner
• Adoniran barbosa
• Adoniran Barbosa
• Adonis aestivalis
• Adonis annua
• Adonis autumnale
• Adonis autumnalis
• Adonis' belt
• Adonis belt
• Adonis blue butterfly
• Adonis flos