"Ægis" has entered modern English to mean a shield, protection, or sponsorship, originally from the name of the mythological protective shield of Zeus. The name has been extended to many other entities, and the concept of a protective shield is found in other mythologies, while its form varies across sources.

Aégis is the third music album of Norwegian metal band Theatre of Tragedy, and the last album of their musical period defined by gothic stylings and Early Modern English lyrics.

Aegis can refer to:

• Aegis, the shield of the Greek god Zeus, or a shield-shaped ancient Egyptian amulet
• Aegis combat system, a US naval missile guidance system
• Aegis Ballistic Missile Defense System, a US missile defense system
• Aegis Defence Services, a United Kingdom-based security services company
• Kimber Aegis II, an M1911 handgun model made by Kimber Manufacturing