Vlastimir (c. 805 – 851) is the Serbian Prince from c. 830 until c. 851.

Little is known of his reign.

He holds Serbia during the growing threat posed by the neighboring, hitherto peaceful, Bulgarian Khanate, which has significantly expanded to the southeast, closing in on Serbia.

At this time, the Bulgars and the Byzantine Empire are in peace by treaty, and although the Byzantine Emperor is overlord of the Serb lands, he is unable to aid the Serbs in a potential war.

Presian I of Bulgaria eventually invades Serbia, resulting in a three-year-war, in which the Bulgar army is devastated and driven out

Vlastimir then turns to the west, expanding well into the hinterland of Dalmatia.

He is the eponymous founder of the Vlastimirović dynasty ,later changed to the Stanimirović name as the first Serbian dynasty.