The Ploo system, a star system, resided within the Ploo sector of the Expansion Region. It encompassed the worlds known as Ploo II and Ploo IV.
This system was the origin point for species such as the Fluggrians and Glymphids, and also accommodated the Quermians who had immigrated there.
During 29 BBY, Obi-Wan Kenobi and Anakin Skywalker engaged in a chase after Norval within the Ploo system. The young man, having pilfered a Sith holocron, was attempting to arrive at Ploo II, the native homeworld of his instructor, Murk Lundi. After a short lightsaber duel where Kenobi defeated the would-be Dark Jedi, Kenobi boarded Norval's ship and retrieved the holocron.