The Cirth script was created by J. R. R. Tolkien for writing the elvish and dwarvish languages spoken in the mythological world of Middle-earth. The shapes of the Cirth are based on the Futhark runes, and they are used in Middle-earth for writing inscriptions on wood and stone, in the same way that runes have been used in the real world.

Each rune generally represents one sound, and each sound is represented by one rune. Cirth was used for the Khuzdûl, Sindarin, and Quenya languages, but some signs represent different sounds in different languages, and other signs are only used in one or two of the three languages. Some of the Cirth also had two forms, which could be glyph variants in one language, but represent two different sounds in another.

The Cirth script was written from left to right with no punctuation.