Peter I of Bourbon (1311 – 19 September 1356, Poitiers) was the second Duke of Bourbon, from 1342 to his death. Peter was son of Louis I of Bourbon, whom he also succeeded as Grand Chamberlain of France, and Mary of Avesnes. Duke Peter is reported to have been somewhat mentally unstable, a trait of nervous breakdowns presumably hereditary that showed clearly for example in his daughter Joan of Bourbon, the queen, and in her son, king Charles VI of France, as well as in Peter's only surviving son, Duke Louis II.