The Ralltiir underground referred to the local Rebel resistance on the planet Ralltiir following the Galactic Empire's subjugation of the planet in 1 BBY. Members of the underground included Pharl McQuarrie and Jeroen Webb, both of whom would go on to join the Alliance to Restore the Republic proper. Thanks largely due to McQuarrie's efforts, the Ralltiir underground helped pass along information regarding the first Death Star to Princess Leia Organa, eventually resulting in the battlestation's destruction at the Battle of Yavin.