Yaddle was a Jedi Master and member of the Jedi High Council during the last years of the Galactic Republic and a Force-sensitive female being of the same species as Grand Master Yoda. She trained a Thisspiasian Padawan, Oppo Rancisis, who eventually joined Yaddle on the High Council by the time of the Invasion of Naboo.
In 32 BBY, Qui-Gon Jinn brought the Chosen One Anakin Skywalker to the Jedi Temple on Coruscant where he met Yaddle and the Jedi elders. After the Battle of Naboo, Yaddle took a less active role in the Jedi Order's affairs and was no longer on the High Council by the time of the Clone Wars.
During the rise of the Galactic Empire, the Sith Lord Darth Vader encountered apparitions of several Jedi, including Yaddle, while experiencing a series of Force visions.