Eustratius of Nicaea (Greek: Εὐστράτιος; c. 1050/1060-c. 1120) was Metropolitan bishop of Nicaea in the early 12th century. He wrote commentaries to Aristotle's second book of Analytica and the Ethica Nicomachea. Two commentaries by Eustratius on the works of Aristotle survive: * Commentary on the Posterior Analytics, book 2 * Commentary on the Nicomachean Ethics, books 1 and 6