Petrislav (Serbian Cyrillic: Петрислав) was ruler of Duklja (or Diokleia), the most powerful Serbian principality of the time, until his death in around 1000. It is unknown when his reign started. The only preserved medieval source that mentions Petrislav is the Chronicle of the Priest of Duklja. Historians identify him with Peter of Diokleia whose seal was found in the 19th century, which makes Petrislav the earliest Duklja's ruler whose existence is confirmed by primary historical sources.
According to the chronicle, after his father's death, the rule was divided among his three sons: Petrislav ruled Zeta, while Dragimir ruled Travunia and Zachumlia (to the west), and Miroslav ruled Podgoria (to the north). After the youngest brother Miroslav died, Petrislav, as the oldest, inherited his land, thus bringing the whole of Duklja (Zeta and Podgoria) under his rule.
Petrislav was buried in the Church of the Holy Virgin Mary in Krajina. He was succeeded by his son Jovan Vladimir.