Mestwin II, Mszczuj II or Mściwój II (died 25 December 1294) was a duke of Eastern Pomerania in years 1266-1294.

Mestwin II was a son of duke Swietopelk. Initially he was a duke of the Swiecie district (since 1266) and of Gdansk district (since 1271). Later had united all dictricts and become the sole ruler of all Eastern Pomerania.

Because he had no sons, he has concluded the Treaty of Kepno in 1282 making duke Przemysl II of Poland, his successor in all his possessions, what was confirmed by the estates of the duchy (early parliamentarism).