Octahedron is the fifth full-length studio album by American progressive rock band the Mars Volta, released on June 23, 2009. The album was released by Warner Bros. Records in North America and Mercury Records worldwide. It is the last studio album to feature drummer Thomas Pridgen and guitarist John Frusciante, and the first not to feature contributions from keyboardist Isaiah "Ikey" Owens and multi-instrumentalist Adrián Terrazas-González.

The Mars Volta is an American progressive rock band from El Paso, formed in 2001. The band's only constant members are Omar Rodríguez-López and Cedric Bixler-Zavala, whose partnership forms the core of the band. The band's current line-up also includes founding member Eva Gardner (bass), Omar's brother Marcel Rodriguez-Lopez, Leo Genovese and Linda-Philomène Tsoungui (drums).