The Ilidarians were a Delta Quadrant species to which USS Voyager crew members Commander Chakotay and Lieutenant Tuvok conducted a trade mission in 2371. On the way back, they were attacked by the Komar. (VOY: "Cathexis")

This species was only mentioned in dialogue.
Neelix informed the Voyager crew of a planet called Ilidaria in "Parallax" (set earlier the same year) which held a technologically-advanced civilization that was "quite friendly, most of time". The article on the Ilidarian species mentions the events of that episode, suggesting that when Neelix was talking about the inhabitants of Ilidaria he was talking about the Ilidarians. However, the entry also states the name of the Ilidarian homeworld as unspecified.