Kosztowy (German: Kostow) is a quarter of the city of Mysłowice in the Silesian Voivodship of Poland.

In the course of a major re-organisation of municipal borders in Upper Silesia it was incorporated into Mysłowice together with Wesoła and Dziećkowice.

In 1391 Duke Johann II (the Iron) gave the large forests surrounding Kosztowy, Imielin and Gross Chelm to the Bishop of Kraków.

In 1807 it became part of the Principality of Siewierz governed by the French marshal Jean Lannes.

Near Kosztowy there is an FM- and TV-transmission facility with a 355-metre-high (1,165 ft) guyed mast.