Petrovice u Karviné  (1920-1952: Petrovice) (Polish: Piotrowice koło Karwiny , German: Petrowitz bei Freistadt) is a municipality in Karviná District, Moravian-Silesian Region, Czech Republic. It has a population of 5,350 (2011), which makes it the second largest municipality in the Czech Republic without an official town status. 13% of the population are the ethnic Poles, 1,2% are Slovaks and also 1,2% Silesians. Around 22,7% of the population is religious (mostly Roman-Catholic), which is about the double of the national average. It lies on the border with Poland, in the historical region of Cieszyn Silesia.