Otto II (c. 995 – 7 September 1047), a member of the Ezzonid dynasty, was Count Palatine of Lotharingia from 1034 until 1045 and Duke of Swabia from 1045 until his death.
Otto's elder brother Herman became Archbishop of Cologne in 1036; his sister Richeza married the Polish king Mieszko II Lambert in 1013.
In turn Henry vested him with the princeless Duchy of Swabia, which he had seized upon the early death of Duke Herman IV.
At Easter on 7 April 1045 in Goslar, the ducal title was awarded to Otto; in exchange, he gave up the office of count palatine, which was bestowed on his cousin Henry I.
He was buried in Brauweiler Abbey; the ceremony was held by his brother-in-law, Bishop Bruno of Toul, the later Pope Leo IX.