In the fictional universe of Warhammer 40,000, the Raven Guard are one of the original first founding chapters of Space Marines. The primarch of the Raven Guard is Corax, which is part of the Latin for raven (the full being corvus corax). Their homeworld is Deliverance, which was renamed from Lycaeum.

The Raven Guard are known for being hot-headed and combat-oriented, especially shown in their successors the Raptors in the Warhammer 40,000 novel Firewarrior by Simon Spurrier. They are also rightly feared for the units of Assault Marines they field, who use a pair of lightning claws instead of the usual bolt pistol and chainsword . One of the new Space Marine characters in the 4th edition Codex, Captain Shrike (named after a British bird of prey that spears it's kills on branches and barbed wire), is part of such a unit.

The Raven Guard were involved in the Drop Site Massacare in the Warhammer 40,000 back-story, where four Legions turned to Chaos. By the end of the Horus Heresy, the Raven Guard were all but annhilated. It is rumoured that Corax used cloning technology to replenish the Chapter's numbers.

Successor chapters include the Black Guard, Revilers and Raptors.