Mistislaw, also known as Mstislav (died after 1018), was an Elbe Slavic prince of the Nakonid lineage and ruled over the Obotrites in what is now Mecklenburg and eastern Holstein from 990/995 to 1018.

The Nakonids were among the most powerful Christian Slavic princes in the second half of the 10th century. In the retinue of the Saxon Duke Bernhard I, Mistislaw participated in Otto II's campaign against the Saracens in southern Italy in 982, from which he returned with only a few survivors. In the subsequent Slavic revolt of 983, the Nakonids relinquished their sovereignty over several Obotrite branches to the victorious Lutici. Upon the death of his father, Mstivoj, in 990 or 995, Mistislaw attempted to establish royal rule over the remaining peoples. While he managed to secure the support of the Church and the Empire, the opposition within the Obotrites joined forces with the Lutici. From 1003 onwards, Mistislaw's ability to secure Saxon support was eroded by Henry II's alliance with the Lutici against the Polish prince Boleslaw I. This ultimately resulted in Mistislaw's inability to assert his authority. In February 1018, the Lutici invaded the Obotrite kingdom, incited unrest among the population, and compelled Mistislaw to seek refuge in the Saxon Bardengau.

The majority of recent research views Mistislaw as a Christian Slavic prince with close ties to the Holy Roman Empire. This research suggests that his attempt to reorganise the Obotrite kingdom from a personal state to a territorial state failed, despite the support of the Church and the Saxon duchy.

Mistislaw, also known as Mistizlavus and Missizla in historical sources, was the son of the Obotritic sovereign (Samtherrscher), Mstivoj. He had two sisters, Tove and Hodica. A marriage to the niece of the Saxon Duke Bernhard I was unsuccessful in 983 due to the opposition of Dietrich of Haldensleben. Mistislaw had a son, Pribignew, with an unknown wife, who assumed control of the confederation around 1020 with the support of Danish and Saxon forces.

Before assuming the role of ruler, Mistislaw participated in Emperor Otto II's Italian campaign in 982 as a representative of the Nakonid family. At the head of a delegation of Obotrite armoured horsemen, he crossed the Alps in 981/982 in the wake of the Saxon Duke Bernhard I to reinforce the imperial army in the southern part of the empire. At this juncture, the emperor initiated a military campaign against the Saracens, who had advanced from Sicily to the southern Italian mainland under the leadership of their emir Abu al-Qasim. The contingent led by Mistislaw is said to have consisted of 1,000 armoured horsemen. By medieval standards, this number is hardly believable, particularly when one considers that the emperor had only requested a total of 2090 armoured riders from the northern part of the empire in his call-up order. Nevertheless, the number of Obotrite warriors must have been exceptionally high, as Bernhard I promised the marriage of his niece to Mistislaw in return for their participation in the campaign, thus creating a dynastic connection between the two princely houses. While Bernhard I was compelled to return to the north at an early stage due to an invasion by the Danes, the vast majority of the Abodrites perished in Italy. Although their ultimate fate remains unknown, it seems likely that they participated in the Battle of Cape Colonna, in which the imperial army was decisively defeated on 15 July 982.

Mistislaw returned to Mecklenburg with the few survivors. Upon demanding the fulfilment of the marriage promise, Count Dietrich von Haldensleben refused to provide him with the bride, stating that a duke's blood relative should not be given to a dog. It seems probable that Dietrich's reasons for opposing a dynastic union between the Billungers and the Nakonids were power-political. As Margrave of the Nordmark, he competed with the Billungers and Nakonids for influence in the Circipanian territory, which was traditionally subject to Obotrite rule. Conversely, it seems unlikely that Dietrich's ethnic reservations about a marriage between the Slavic prince's son and the Saxon princess were a significant factor in his opposition to the union. Such unions were not uncommon at the time. In 978, Dietrich himself had sponsored the marriage of his eldest daughter Oda to the Polish prince Mieszko I, and his other daughter Mathilde had married the Hevelli prince Pribislaw. Mistislaw's father, Mstivoj, was married to the sister of the Oldenburg bishop, Wago, and a relative of the Saxon duke, Bernhard I, Weldrud, had been given in marriage to the Wagrian prince, Sederich.

As the sovereign of the Obotrite confederation, Mistislaw ruled over the eponymous Obotrite branch on both sides of Lake Schwerin and the princes of the various branches. They owed him military allegiance and tribute.

The date of Mistislav's accession to power is uncertain. The majority of research has concentrated on the years 990 and 995. Christian Lübke has proposed that a significant shift in Obotrite policy could be identified from 990 onwards, which would indicate a change in leadership. In contrast, Peter Donat and Jürgen Petersohn propose that a friendly visit by King Otto III to Mecklenburg in September 995 could have taken place on the occasion of Mistislav's enthronement.