Queen Jamillia was an NPC, elected Queen of Naboo after Padme Amidala's term as Queen had expired.
Silence of the Clones[]
Padme Amidala, R2-D2, and Anakin arrived on Naboo to investigate the stolen Peace Moon plans, where they were greeted by the current queen, Queen Jamillia and Sio Bibble. Padme ordered Bibble's arrest, but the Queen overrode her, pointing out that they needed to find the stolen plans for the Peace Moon. Anakin suggested they take a tour of Naboo, to see if they could figure out who would benefit from the current status quo.
A New Generation[]
If Queen Jamillia was still alive 22 years later and living on Naboo, she was most likely killed along with everyone else on Naboo when Darth Vader ordered the planet's destruction from the Peace Moon's laser.