Ostromir (Остромир in Russian; Christian name - Joseph) (? - after 1057) was a statesman, voivod and posadnik of Novgorod in 1054-1057. He is known to have ordered his diak Gregory to write the so-called Ostromir Codex (Остромировo евангелиe, or Ostromir's Gospel). Ostromir was a relative of Izyaslav Yaroslavich and a practical co-ruler of the Kievan Rus. According to the First Chronicle of Sophia, Ostromir died in 1056 during his military campaign against the Chudes. It is highly unlikely, however, since the afterword of the Ostromir Codex clearly states that he was still alive in 1057.

Voivod Vyshata was Ostromir's son. Yan Vyshatich, an active participant in creation of the Primary Chronicle, was Ostromir's grandson.