The Elder Sign is a magical icon that appears in the Cthulhu Mythos.
The most prominent description is given in The Lurker at the Threshold. There it is said to be like a five-pointed star with a pillar of fire or an eye in the middle.
The Elder Sign is an emblem associated with the Elder Gods. It is said to have been designed by N'tse-Kaambl and among its powers is the ability to repel evil monsters and, according to some, it is its power that holds the Great Old Ones' prisoners.
- A Fantasy Flight Games game is named after the Elder Sign.
- The Elder Sign appears in the game Dungeons and Dragons.
- The Elder Sign has been mentioned in The League of Extraordinary Gentlemen.
- In the Games of Cthulhu video games for Internet browsers "The Necronomicon" and "The Necronomicon - Book of Dead Names", the Symbol represents the defense factor against non-physical attacks, being able to completely counter the damage if it is high enough. The illustration of the "Dispel" card, which removes invincibility status (which is awarded by the "Elder Sign" card) and defense, shows a pentagram the same color as the defense icon being erased.
- In the Digimon franchise, the Digimon AncientWisemon has an attack called the "Elder Sign". Unlike its incarnation in the mythos, this ability is used to summon Great Old Ones. Likewise, the Digimon Daemon and Mephistomon carry in their design a small pentagram similar to the Elder Sign, although inverted, perhaps hinting that their object is exactly the opposite.