Otto Bolesławowic (1000–1033) was a Polish prince member of the House of Piast.
He was the third son of Bolesław I the Brave but the second born from his third marriage with Emnilda, daughter of Dobromir, a Slavic prince of Lusatia.
Otto was the youngest child of his parents; he was named after Emperor Otto III, who probably stood as his godfather. In 1018 he was present in his father's fourth and last marriage with Oda of Meissen on Cziczani.
After the death of his father in 1025, Otto expected to obtain a part of Bolesław I's heritage, according to the Slavic custom, under which a father should divide his legacy among all his sons. However, because Poland became a Kingdom, the country cannot be divided, and in consequence Otto receive nothing from their father's legacy. The only heir and successor of Bolesław I was Mieszko II Lambert, his eldest son from his marriage with Emnilda.
With Otto, his half-brother Bezprym was also disinherited. Bezprym was the older son of Bolesław I by his second wife, the Hungarian princess Judith, who was repudiated shortly after Bezprym was born. Maybe for this he was always been disliked by his father, who determined that Mieszko II was his only heir.
Soon after Mieszko II took the government of Poland, he either expelled or forced to flee his brothers from the country. Otto moved to Germany, probably to Meissen at the court of his sister Regelinda. In 1031 the combined attack of the Kievan and German forces led to the downfall of Mieszko II, who had to flee to Bohemia. The government was taken by Bezprym alone; this probably caused Otto's resentment and his approach to Mieszko II. As a result, in the first half of 1032 Bezprym was murdered probably thanks to a conspiracy organized by his half-brothers.
On 7 July 1032, the Emperor Conrad II in Merseburg divided Poland between Mieszko II, Otto, and their cousin Dytryk (grandson of Mieszko I and his third wife Oda). It's unknown were was exactly divided the country between them.
Otto died in 1033 of natural causes, or killed by his own vassals. His place of burial is unknown.