Slezská Ostrava (Polish: Śląska Ostrawa, lit. Silesian Ostrava), till 1919 Polnisch Ostrau (Czech: Polská Ostrava, Polish: Polska Ostrawa, lit. Polish Ostrava) is a district of the city of Ostrava, Moravian-Silesian Region in the Czech Republic. It lies in the historical region of Cieszyn Silesia, not counting Koblov and Antošovice lying north-west from the Oder river in the Hlučín Region.
It comprises historical city of Slezská Ostrava as well as market town of Hrušov and villages Antošovice, Heřmanice, Koblov, Kunčice, Kunčičky and Muglinov.
Ostrava was first mentioned in the document of Pope Gregory IX issued for Benedictine abbey in Tyniec in 1229 as Ostrawa. Politically it belonged then to the Duchy of Opole and Racibórz, however it lay on the river Ostravice along which a border between the Silesia and Morava was first regulated in 1261. After founding the town of Moravská Ostrava between 1268 and 1278 on Moravian side, the village left on the Silesian side was called in contrary Slavic and later Polish. Since 1290 it belonged to the Duchy of Teschen, which in 1327 became a fee of Kingdom of Bohemia, wchich after 1526 became part of the Habsburg Monarchy.